* [PATCH net-next 0/9] rxrpc: Preparation for slow-start algorithm [ver #2]
@ 2016-09-22 8:22 David Howells
2016-09-22 8:22 ` [PATCH net-next 1/9] rxrpc: Don't store the rxrpc header in the Tx queue sk_buffs " David Howells
` (9 more replies)
0 siblings, 10 replies; 11+ messages in thread
From: David Howells @ 2016-09-22 8:22 UTC (permalink / raw)
To: netdev; +Cc: dhowells, linux-afs, linux-kernel
Here are some patches that prepare for improvements in ACK generation and
for the implementation of the slow-start part of the protocol:
(1) Stop storing the protocol header in the Tx socket buffers, but rather
generate it on the fly. This potentially saves a little space and
makes it easier to alter the header just before transmission (the
flags may get altered and the serial number has to be changed).
(2) Mask off the Tx buffer annotations and add a flag to record which ones
have already been resent.
(3) Track RTT on a per-peer basis for use in future changes. Tracepoints
are added to log this.
(4) Send PING ACKs in response to incoming calls to elicit a PING-RESPONSE
ACK from which RTT data can be calculated. The response also carries
other useful information.
(5) Expedite PING-RESPONSE ACK generation from sendmsg. If we're actively
using sendmsg, this allows us, under some circumstances, to avoid
having to rely on the background work item to run to generate this
ACK.
This requires ktime_sub_ms() to be added.
(6) Set the REQUEST-ACK flag on some DATA packets to elicit ACK-REQUESTED
ACKs from which RTT data can be calculated.
(7) Limit the use of pings and ACK requests for RTT determination.
Changes:
(V2) Don't use the C division operator for 64-bit division. One instance
should use do_div() and the other should be using nsecs_to_jiffies().
The last two patches got transposed, leading to an undefined symbol
in one of them.
Reported-by: kbuild test robot <lkp@intel.com>
The patches can be found here also:
http://git.kernel.org/cgit/linux/kernel/git/dhowells/linux-fs.git/log/?h=rxrpc-rewrite
Tagged thusly:
git://git.kernel.org/pub/scm/linux/kernel/git/dhowells/linux-fs.git
rxrpc-rewrite-20160922-v2
David
---
David Howells (9):
rxrpc: Don't store the rxrpc header in the Tx queue sk_buffs
rxrpc: Add re-sent Tx annotation
rxrpc: Add per-peer RTT tracker
rxrpc: Send pings to get RTT data
rxrpc: Expedite ping response transmission
rxrpc: Add ktime_sub_ms()
rxrpc: Obtain RTT data by requesting ACKs on DATA packets
rxrpc: Reduce the number of ACK-Requests sent
rxrpc: Reduce the number of PING ACKs sent
include/linux/ktime.h | 5 ++
include/trace/events/rxrpc.h | 61 ++++++++++++++++++++++
net/rxrpc/ar-internal.h | 47 ++++++++++++-----
net/rxrpc/call_event.c | 56 ++++++++++----------
net/rxrpc/conn_object.c | 1
net/rxrpc/input.c | 100 ++++++++++++++++++++++++++++++++++--
net/rxrpc/misc.c | 25 ++++++---
net/rxrpc/output.c | 117 ++++++++++++++++++++++++++++++++----------
net/rxrpc/peer_event.c | 41 +++++++++++++++
net/rxrpc/peer_object.c | 1
net/rxrpc/rxkad.c | 8 +--
net/rxrpc/sendmsg.c | 56 ++++----------------
net/rxrpc/sysctl.c | 2 -
13 files changed, 390 insertions(+), 130 deletions(-)
^ permalink raw reply [flat|nested] 11+ messages in thread
* [PATCH net-next 1/9] rxrpc: Don't store the rxrpc header in the Tx queue sk_buffs [ver #2]
2016-09-22 8:22 [PATCH net-next 0/9] rxrpc: Preparation for slow-start algorithm [ver #2] David Howells
@ 2016-09-22 8:22 ` David Howells
2016-09-22 8:22 ` [PATCH net-next 2/9] rxrpc: Add re-sent Tx annotation " David Howells
` (8 subsequent siblings)
9 siblings, 0 replies; 11+ messages in thread
From: David Howells @ 2016-09-22 8:22 UTC (permalink / raw)
To: netdev; +Cc: dhowells, linux-afs, linux-kernel
Don't store the rxrpc protocol header in sk_buffs on the transmit queue,
but rather generate it on the fly and pass it to kernel_sendmsg() as a
separate iov. This reduces the amount of storage required.
Note that the security header is still stored in the sk_buff as it may get
encrypted along with the data (and doesn't change with each transmission).
Signed-off-by: David Howells <dhowells@redhat.com>
---
net/rxrpc/ar-internal.h | 5 +--
net/rxrpc/call_event.c | 11 +-----
net/rxrpc/conn_object.c | 1 -
net/rxrpc/output.c | 83 ++++++++++++++++++++++++++++++++---------------
net/rxrpc/rxkad.c | 8 ++---
net/rxrpc/sendmsg.c | 51 +++++------------------------
6 files changed, 71 insertions(+), 88 deletions(-)
diff --git a/net/rxrpc/ar-internal.h b/net/rxrpc/ar-internal.h
index 034f525f2235..f021df4a6a22 100644
--- a/net/rxrpc/ar-internal.h
+++ b/net/rxrpc/ar-internal.h
@@ -385,10 +385,9 @@ struct rxrpc_connection {
int debug_id; /* debug ID for printks */
atomic_t serial; /* packet serial number counter */
unsigned int hi_serial; /* highest serial number received */
+ u32 security_nonce; /* response re-use preventer */
u8 size_align; /* data size alignment (for security) */
- u8 header_size; /* rxrpc + security header size */
u8 security_size; /* security header size */
- u32 security_nonce; /* response re-use preventer */
u8 security_ix; /* security type */
u8 out_clientflag; /* RXRPC_CLIENT_INITIATED if we are client */
};
@@ -946,7 +945,7 @@ extern const s8 rxrpc_ack_priority[];
* output.c
*/
int rxrpc_send_call_packet(struct rxrpc_call *, u8);
-int rxrpc_send_data_packet(struct rxrpc_connection *, struct sk_buff *);
+int rxrpc_send_data_packet(struct rxrpc_call *, struct sk_buff *);
void rxrpc_reject_packets(struct rxrpc_local *);
/*
diff --git a/net/rxrpc/call_event.c b/net/rxrpc/call_event.c
index 7d1b99824ed9..6247ce25eb21 100644
--- a/net/rxrpc/call_event.c
+++ b/net/rxrpc/call_event.c
@@ -139,7 +139,6 @@ void rxrpc_propose_ACK(struct rxrpc_call *call, u8 ack_reason,
*/
static void rxrpc_resend(struct rxrpc_call *call)
{
- struct rxrpc_wire_header *whdr;
struct rxrpc_skb_priv *sp;
struct sk_buff *skb;
rxrpc_seq_t cursor, seq, top;
@@ -201,15 +200,8 @@ static void rxrpc_resend(struct rxrpc_call *call)
skb = call->rxtx_buffer[ix];
rxrpc_get_skb(skb, rxrpc_skb_tx_got);
spin_unlock_bh(&call->lock);
- sp = rxrpc_skb(skb);
-
- /* Each Tx packet needs a new serial number */
- sp->hdr.serial = atomic_inc_return(&call->conn->serial);
- whdr = (struct rxrpc_wire_header *)skb->head;
- whdr->serial = htonl(sp->hdr.serial);
-
- if (rxrpc_send_data_packet(call->conn, skb) < 0) {
+ if (rxrpc_send_data_packet(call, skb) < 0) {
call->resend_at = now + 2;
rxrpc_free_skb(skb, rxrpc_skb_tx_freed);
return;
@@ -217,6 +209,7 @@ static void rxrpc_resend(struct rxrpc_call *call)
if (rxrpc_is_client_call(call))
rxrpc_expose_client_call(call);
+ sp = rxrpc_skb(skb);
sp->resend_at = now + rxrpc_resend_timeout;
rxrpc_free_skb(skb, rxrpc_skb_tx_freed);
diff --git a/net/rxrpc/conn_object.c b/net/rxrpc/conn_object.c
index 3b55aee0c436..e1e83af47866 100644
--- a/net/rxrpc/conn_object.c
+++ b/net/rxrpc/conn_object.c
@@ -53,7 +53,6 @@ struct rxrpc_connection *rxrpc_alloc_connection(gfp_t gfp)
spin_lock_init(&conn->state_lock);
conn->debug_id = atomic_inc_return(&rxrpc_debug_id);
conn->size_align = 4;
- conn->header_size = sizeof(struct rxrpc_wire_header);
conn->idle_timestamp = jiffies;
}
diff --git a/net/rxrpc/output.c b/net/rxrpc/output.c
index 16e18a94ffa6..817fb0e82d6a 100644
--- a/net/rxrpc/output.c
+++ b/net/rxrpc/output.c
@@ -208,19 +208,42 @@ out:
/*
* send a packet through the transport endpoint
*/
-int rxrpc_send_data_packet(struct rxrpc_connection *conn, struct sk_buff *skb)
+int rxrpc_send_data_packet(struct rxrpc_call *call, struct sk_buff *skb)
{
- struct kvec iov[1];
+ struct rxrpc_connection *conn = call->conn;
+ struct rxrpc_wire_header whdr;
+ struct rxrpc_skb_priv *sp = rxrpc_skb(skb);
struct msghdr msg;
+ struct kvec iov[2];
+ rxrpc_serial_t serial;
+ size_t len;
int ret, opt;
_enter(",{%d}", skb->len);
- iov[0].iov_base = skb->head;
- iov[0].iov_len = skb->len;
+ /* Each transmission of a Tx packet needs a new serial number */
+ serial = atomic_inc_return(&conn->serial);
+
+ whdr.epoch = htonl(conn->proto.epoch);
+ whdr.cid = htonl(call->cid);
+ whdr.callNumber = htonl(call->call_id);
+ whdr.seq = htonl(sp->hdr.seq);
+ whdr.serial = htonl(serial);
+ whdr.type = RXRPC_PACKET_TYPE_DATA;
+ whdr.flags = sp->hdr.flags;
+ whdr.userStatus = 0;
+ whdr.securityIndex = call->security_ix;
+ whdr._rsvd = htons(sp->hdr._rsvd);
+ whdr.serviceId = htons(call->service_id);
+
+ iov[0].iov_base = &whdr;
+ iov[0].iov_len = sizeof(whdr);
+ iov[1].iov_base = skb->head;
+ iov[1].iov_len = skb->len;
+ len = iov[0].iov_len + iov[1].iov_len;
- msg.msg_name = &conn->params.peer->srx.transport;
- msg.msg_namelen = conn->params.peer->srx.transport_len;
+ msg.msg_name = &call->peer->srx.transport;
+ msg.msg_namelen = call->peer->srx.transport_len;
msg.msg_control = NULL;
msg.msg_controllen = 0;
msg.msg_flags = 0;
@@ -234,26 +257,33 @@ int rxrpc_send_data_packet(struct rxrpc_connection *conn, struct sk_buff *skb)
}
}
+ _proto("Tx DATA %%%u { #%u }", serial, sp->hdr.seq);
+
/* send the packet with the don't fragment bit set if we currently
* think it's small enough */
- if (skb->len - sizeof(struct rxrpc_wire_header) < conn->params.peer->maxdata) {
- down_read(&conn->params.local->defrag_sem);
- /* send the packet by UDP
- * - returns -EMSGSIZE if UDP would have to fragment the packet
- * to go out of the interface
- * - in which case, we'll have processed the ICMP error
- * message and update the peer record
- */
- ret = kernel_sendmsg(conn->params.local->socket, &msg, iov, 1,
- iov[0].iov_len);
-
- up_read(&conn->params.local->defrag_sem);
- if (ret == -EMSGSIZE)
- goto send_fragmentable;
-
- _leave(" = %d [%u]", ret, conn->params.peer->maxdata);
- return ret;
+ if (iov[1].iov_len >= call->peer->maxdata)
+ goto send_fragmentable;
+
+ down_read(&conn->params.local->defrag_sem);
+ /* send the packet by UDP
+ * - returns -EMSGSIZE if UDP would have to fragment the packet
+ * to go out of the interface
+ * - in which case, we'll have processed the ICMP error
+ * message and update the peer record
+ */
+ ret = kernel_sendmsg(conn->params.local->socket, &msg, iov, 2, len);
+
+ up_read(&conn->params.local->defrag_sem);
+ if (ret == -EMSGSIZE)
+ goto send_fragmentable;
+
+done:
+ if (ret == 0) {
+ sp->resend_at = jiffies + rxrpc_resend_timeout;
+ sp->hdr.serial = serial;
}
+ _leave(" = %d [%u]", ret, call->peer->maxdata);
+ return ret;
send_fragmentable:
/* attempt to send this message with fragmentation enabled */
@@ -268,8 +298,8 @@ send_fragmentable:
SOL_IP, IP_MTU_DISCOVER,
(char *)&opt, sizeof(opt));
if (ret == 0) {
- ret = kernel_sendmsg(conn->params.local->socket, &msg, iov, 1,
- iov[0].iov_len);
+ ret = kernel_sendmsg(conn->params.local->socket, &msg,
+ iov, 2, len);
opt = IP_PMTUDISC_DO;
kernel_setsockopt(conn->params.local->socket, SOL_IP,
@@ -298,8 +328,7 @@ send_fragmentable:
}
up_write(&conn->params.local->defrag_sem);
- _leave(" = %d [frag %u]", ret, conn->params.peer->maxdata);
- return ret;
+ goto done;
}
/*
diff --git a/net/rxrpc/rxkad.c b/net/rxrpc/rxkad.c
index ae392558829d..88d080a1a3de 100644
--- a/net/rxrpc/rxkad.c
+++ b/net/rxrpc/rxkad.c
@@ -80,12 +80,10 @@ static int rxkad_init_connection_security(struct rxrpc_connection *conn)
case RXRPC_SECURITY_AUTH:
conn->size_align = 8;
conn->security_size = sizeof(struct rxkad_level1_hdr);
- conn->header_size += sizeof(struct rxkad_level1_hdr);
break;
case RXRPC_SECURITY_ENCRYPT:
conn->size_align = 8;
conn->security_size = sizeof(struct rxkad_level2_hdr);
- conn->header_size += sizeof(struct rxkad_level2_hdr);
break;
default:
ret = -EKEYREJECTED;
@@ -161,7 +159,7 @@ static int rxkad_secure_packet_auth(const struct rxrpc_call *call,
_enter("");
- check = sp->hdr.seq ^ sp->hdr.callNumber;
+ check = sp->hdr.seq ^ call->call_id;
data_size |= (u32)check << 16;
hdr.data_size = htonl(data_size);
@@ -205,7 +203,7 @@ static int rxkad_secure_packet_encrypt(const struct rxrpc_call *call,
_enter("");
- check = sp->hdr.seq ^ sp->hdr.callNumber;
+ check = sp->hdr.seq ^ call->call_id;
rxkhdr.data_size = htonl(data_size | (u32)check << 16);
rxkhdr.checksum = 0;
@@ -277,7 +275,7 @@ static int rxkad_secure_packet(struct rxrpc_call *call,
/* calculate the security checksum */
x = (call->cid & RXRPC_CHANNELMASK) << (32 - RXRPC_CIDSHIFT);
x |= sp->hdr.seq & 0x3fffffff;
- call->crypto_buf[0] = htonl(sp->hdr.callNumber);
+ call->crypto_buf[0] = htonl(call->call_id);
call->crypto_buf[1] = htonl(x);
sg_init_one(&sg, call->crypto_buf, 8);
diff --git a/net/rxrpc/sendmsg.c b/net/rxrpc/sendmsg.c
index 6a39ee97a0b7..814b17f23971 100644
--- a/net/rxrpc/sendmsg.c
+++ b/net/rxrpc/sendmsg.c
@@ -134,13 +134,11 @@ static void rxrpc_queue_packet(struct rxrpc_call *call, struct sk_buff *skb,
write_unlock_bh(&call->state_lock);
}
- _proto("Tx DATA %%%u { #%u }", sp->hdr.serial, sp->hdr.seq);
-
if (seq == 1 && rxrpc_is_client_call(call))
rxrpc_expose_client_call(call);
sp->resend_at = jiffies + rxrpc_resend_timeout;
- ret = rxrpc_send_data_packet(call->conn, skb);
+ ret = rxrpc_send_data_packet(call, skb);
if (ret < 0) {
_debug("need instant resend %d", ret);
rxrpc_instant_resend(call, ix);
@@ -151,29 +149,6 @@ static void rxrpc_queue_packet(struct rxrpc_call *call, struct sk_buff *skb,
}
/*
- * Convert a host-endian header into a network-endian header.
- */
-static void rxrpc_insert_header(struct sk_buff *skb)
-{
- struct rxrpc_wire_header whdr;
- struct rxrpc_skb_priv *sp = rxrpc_skb(skb);
-
- whdr.epoch = htonl(sp->hdr.epoch);
- whdr.cid = htonl(sp->hdr.cid);
- whdr.callNumber = htonl(sp->hdr.callNumber);
- whdr.seq = htonl(sp->hdr.seq);
- whdr.serial = htonl(sp->hdr.serial);
- whdr.type = sp->hdr.type;
- whdr.flags = sp->hdr.flags;
- whdr.userStatus = sp->hdr.userStatus;
- whdr.securityIndex = sp->hdr.securityIndex;
- whdr._rsvd = htons(sp->hdr._rsvd);
- whdr.serviceId = htons(sp->hdr.serviceId);
-
- memcpy(skb->head, &whdr, sizeof(whdr));
-}
-
-/*
* send data through a socket
* - must be called in process context
* - caller holds the socket locked
@@ -232,7 +207,7 @@ static int rxrpc_send_data(struct rxrpc_sock *rx,
space = chunk + call->conn->size_align;
space &= ~(call->conn->size_align - 1UL);
- size = space + call->conn->header_size;
+ size = space + call->conn->security_size;
_debug("SIZE: %zu/%zu/%zu", chunk, space, size);
@@ -248,9 +223,9 @@ static int rxrpc_send_data(struct rxrpc_sock *rx,
ASSERTCMP(skb->mark, ==, 0);
- _debug("HS: %u", call->conn->header_size);
- skb_reserve(skb, call->conn->header_size);
- skb->len += call->conn->header_size;
+ _debug("HS: %u", call->conn->security_size);
+ skb_reserve(skb, call->conn->security_size);
+ skb->len += call->conn->security_size;
sp = rxrpc_skb(skb);
sp->remain = chunk;
@@ -312,33 +287,23 @@ static int rxrpc_send_data(struct rxrpc_sock *rx,
seq = call->tx_top + 1;
- sp->hdr.epoch = conn->proto.epoch;
- sp->hdr.cid = call->cid;
- sp->hdr.callNumber = call->call_id;
sp->hdr.seq = seq;
- sp->hdr.serial = atomic_inc_return(&conn->serial);
- sp->hdr.type = RXRPC_PACKET_TYPE_DATA;
- sp->hdr.userStatus = 0;
- sp->hdr.securityIndex = call->security_ix;
sp->hdr._rsvd = 0;
- sp->hdr.serviceId = call->service_id;
+ sp->hdr.flags = conn->out_clientflag;
- sp->hdr.flags = conn->out_clientflag;
if (msg_data_left(msg) == 0 && !more)
sp->hdr.flags |= RXRPC_LAST_PACKET;
else if (call->tx_top - call->tx_hard_ack <
call->tx_winsize)
sp->hdr.flags |= RXRPC_MORE_PACKETS;
- if (more && seq & 1)
+ if (seq & 1)
sp->hdr.flags |= RXRPC_REQUEST_ACK;
ret = conn->security->secure_packet(
- call, skb, skb->mark,
- skb->head + sizeof(struct rxrpc_wire_header));
+ call, skb, skb->mark, skb->head);
if (ret < 0)
goto out;
- rxrpc_insert_header(skb);
rxrpc_queue_packet(call, skb, !msg_data_left(msg) && !more);
skb = NULL;
}
^ permalink raw reply related [flat|nested] 11+ messages in thread
* [PATCH net-next 2/9] rxrpc: Add re-sent Tx annotation [ver #2]
2016-09-22 8:22 [PATCH net-next 0/9] rxrpc: Preparation for slow-start algorithm [ver #2] David Howells
2016-09-22 8:22 ` [PATCH net-next 1/9] rxrpc: Don't store the rxrpc header in the Tx queue sk_buffs " David Howells
@ 2016-09-22 8:22 ` David Howells
2016-09-22 8:22 ` [PATCH net-next 3/9] rxrpc: Add per-peer RTT tracker " David Howells
` (7 subsequent siblings)
9 siblings, 0 replies; 11+ messages in thread
From: David Howells @ 2016-09-22 8:22 UTC (permalink / raw)
To: netdev; +Cc: dhowells, linux-afs, linux-kernel
Add a Tx-phase annotation for packet buffers to indicate that a buffer has
already been retransmitted. This will be used by future congestion
management. Re-retransmissions of a packet don't affect the congestion
window managment in the same way as initial retransmissions.
Signed-off-by: David Howells <dhowells@redhat.com>
---
net/rxrpc/ar-internal.h | 2 ++
net/rxrpc/call_event.c | 28 +++++++++++++++++++---------
net/rxrpc/input.c | 14 +++++++++++---
3 files changed, 32 insertions(+), 12 deletions(-)
diff --git a/net/rxrpc/ar-internal.h b/net/rxrpc/ar-internal.h
index f021df4a6a22..dcf54e3fb478 100644
--- a/net/rxrpc/ar-internal.h
+++ b/net/rxrpc/ar-internal.h
@@ -505,6 +505,8 @@ struct rxrpc_call {
#define RXRPC_TX_ANNO_UNACK 1
#define RXRPC_TX_ANNO_NAK 2
#define RXRPC_TX_ANNO_RETRANS 3
+#define RXRPC_TX_ANNO_MASK 0x03
+#define RXRPC_TX_ANNO_RESENT 0x04
#define RXRPC_RX_ANNO_JUMBO 0x3f /* Jumbo subpacket number + 1 if not zero */
#define RXRPC_RX_ANNO_JLAST 0x40 /* Set if last element of a jumbo packet */
#define RXRPC_RX_ANNO_VERIFIED 0x80 /* Set if verified and decrypted */
diff --git a/net/rxrpc/call_event.c b/net/rxrpc/call_event.c
index 6247ce25eb21..34ad967f2d81 100644
--- a/net/rxrpc/call_event.c
+++ b/net/rxrpc/call_event.c
@@ -144,7 +144,7 @@ static void rxrpc_resend(struct rxrpc_call *call)
rxrpc_seq_t cursor, seq, top;
unsigned long resend_at, now;
int ix;
- u8 annotation;
+ u8 annotation, anno_type;
_enter("{%d,%d}", call->tx_hard_ack, call->tx_top);
@@ -165,14 +165,16 @@ static void rxrpc_resend(struct rxrpc_call *call)
for (seq = cursor + 1; before_eq(seq, top); seq++) {
ix = seq & RXRPC_RXTX_BUFF_MASK;
annotation = call->rxtx_annotations[ix];
- if (annotation == RXRPC_TX_ANNO_ACK)
+ anno_type = annotation & RXRPC_TX_ANNO_MASK;
+ annotation &= ~RXRPC_TX_ANNO_MASK;
+ if (anno_type == RXRPC_TX_ANNO_ACK)
continue;
skb = call->rxtx_buffer[ix];
rxrpc_see_skb(skb, rxrpc_skb_tx_seen);
sp = rxrpc_skb(skb);
- if (annotation == RXRPC_TX_ANNO_UNACK) {
+ if (anno_type == RXRPC_TX_ANNO_UNACK) {
if (time_after(sp->resend_at, now)) {
if (time_before(sp->resend_at, resend_at))
resend_at = sp->resend_at;
@@ -181,7 +183,7 @@ static void rxrpc_resend(struct rxrpc_call *call)
}
/* Okay, we need to retransmit a packet. */
- call->rxtx_annotations[ix] = RXRPC_TX_ANNO_RETRANS;
+ call->rxtx_annotations[ix] = RXRPC_TX_ANNO_RETRANS | annotation;
}
call->resend_at = resend_at;
@@ -194,7 +196,8 @@ static void rxrpc_resend(struct rxrpc_call *call)
for (seq = cursor + 1; before_eq(seq, top); seq++) {
ix = seq & RXRPC_RXTX_BUFF_MASK;
annotation = call->rxtx_annotations[ix];
- if (annotation != RXRPC_TX_ANNO_RETRANS)
+ anno_type = annotation & RXRPC_TX_ANNO_MASK;
+ if (anno_type != RXRPC_TX_ANNO_RETRANS)
continue;
skb = call->rxtx_buffer[ix];
@@ -220,10 +223,17 @@ static void rxrpc_resend(struct rxrpc_call *call)
* received and the packet might have been hard-ACK'd (in which
* case it will no longer be in the buffer).
*/
- if (after(seq, call->tx_hard_ack) &&
- (call->rxtx_annotations[ix] == RXRPC_TX_ANNO_RETRANS ||
- call->rxtx_annotations[ix] == RXRPC_TX_ANNO_NAK))
- call->rxtx_annotations[ix] = RXRPC_TX_ANNO_UNACK;
+ if (after(seq, call->tx_hard_ack)) {
+ annotation = call->rxtx_annotations[ix];
+ anno_type = annotation & RXRPC_TX_ANNO_MASK;
+ if (anno_type == RXRPC_TX_ANNO_RETRANS ||
+ anno_type == RXRPC_TX_ANNO_NAK) {
+ annotation &= ~RXRPC_TX_ANNO_MASK;
+ annotation |= RXRPC_TX_ANNO_UNACK;
+ }
+ annotation |= RXRPC_TX_ANNO_RESENT;
+ call->rxtx_annotations[ix] = annotation;
+ }
if (after(call->tx_hard_ack, seq))
seq = call->tx_hard_ack;
diff --git a/net/rxrpc/input.c b/net/rxrpc/input.c
index 7ac1edf3aac7..aa261df9fc9e 100644
--- a/net/rxrpc/input.c
+++ b/net/rxrpc/input.c
@@ -388,17 +388,25 @@ static void rxrpc_input_soft_acks(struct rxrpc_call *call, u8 *acks,
{
bool resend = false;
int ix;
+ u8 annotation, anno_type;
for (; nr_acks > 0; nr_acks--, seq++) {
ix = seq & RXRPC_RXTX_BUFF_MASK;
+ annotation = call->rxtx_annotations[ix];
+ anno_type = annotation & RXRPC_TX_ANNO_MASK;
+ annotation &= ~RXRPC_TX_ANNO_MASK;
switch (*acks++) {
case RXRPC_ACK_TYPE_ACK:
- call->rxtx_annotations[ix] = RXRPC_TX_ANNO_ACK;
+ if (anno_type == RXRPC_TX_ANNO_ACK)
+ continue;
+ call->rxtx_annotations[ix] =
+ RXRPC_TX_ANNO_ACK | annotation;
break;
case RXRPC_ACK_TYPE_NACK:
- if (call->rxtx_annotations[ix] == RXRPC_TX_ANNO_NAK)
+ if (anno_type == RXRPC_TX_ANNO_NAK)
continue;
- call->rxtx_annotations[ix] = RXRPC_TX_ANNO_NAK;
+ call->rxtx_annotations[ix] =
+ RXRPC_TX_ANNO_NAK | annotation;
resend = true;
break;
default:
^ permalink raw reply related [flat|nested] 11+ messages in thread
* [PATCH net-next 3/9] rxrpc: Add per-peer RTT tracker [ver #2]
2016-09-22 8:22 [PATCH net-next 0/9] rxrpc: Preparation for slow-start algorithm [ver #2] David Howells
2016-09-22 8:22 ` [PATCH net-next 1/9] rxrpc: Don't store the rxrpc header in the Tx queue sk_buffs " David Howells
2016-09-22 8:22 ` [PATCH net-next 2/9] rxrpc: Add re-sent Tx annotation " David Howells
@ 2016-09-22 8:22 ` David Howells
2016-09-22 8:22 ` [PATCH net-next 4/9] rxrpc: Send pings to get RTT data " David Howells
` (6 subsequent siblings)
9 siblings, 0 replies; 11+ messages in thread
From: David Howells @ 2016-09-22 8:22 UTC (permalink / raw)
To: netdev; +Cc: dhowells, linux-afs, linux-kernel
Add a function to track the average RTT for a peer. Sources of RTT data
will be added in subsequent patches.
The RTT data will be useful in the future for determining resend timeouts
and for handling the slow-start part of the Rx protocol.
Also add a pair of tracepoints, one to log transmissions to elicit a
response for RTT purposes and one to log responses that contribute RTT
data.
Signed-off-by: David Howells <dhowells@redhat.com>
---
include/trace/events/rxrpc.h | 61 ++++++++++++++++++++++++++++++++++++++++++
net/rxrpc/ar-internal.h | 25 ++++++++++++++---
net/rxrpc/misc.c | 8 ++++++
net/rxrpc/peer_event.c | 41 ++++++++++++++++++++++++++++
4 files changed, 131 insertions(+), 4 deletions(-)
diff --git a/include/trace/events/rxrpc.h b/include/trace/events/rxrpc.h
index 75a5d8bf50e1..e8f2afbbe0bf 100644
--- a/include/trace/events/rxrpc.h
+++ b/include/trace/events/rxrpc.h
@@ -353,6 +353,67 @@ TRACE_EVENT(rxrpc_recvmsg,
__entry->ret)
);
+TRACE_EVENT(rxrpc_rtt_tx,
+ TP_PROTO(struct rxrpc_call *call, enum rxrpc_rtt_tx_trace why,
+ rxrpc_serial_t send_serial),
+
+ TP_ARGS(call, why, send_serial),
+
+ TP_STRUCT__entry(
+ __field(struct rxrpc_call *, call )
+ __field(enum rxrpc_rtt_tx_trace, why )
+ __field(rxrpc_serial_t, send_serial )
+ ),
+
+ TP_fast_assign(
+ __entry->call = call;
+ __entry->why = why;
+ __entry->send_serial = send_serial;
+ ),
+
+ TP_printk("c=%p %s sr=%08x",
+ __entry->call,
+ rxrpc_rtt_tx_traces[__entry->why],
+ __entry->send_serial)
+ );
+
+TRACE_EVENT(rxrpc_rtt_rx,
+ TP_PROTO(struct rxrpc_call *call, enum rxrpc_rtt_rx_trace why,
+ rxrpc_serial_t send_serial, rxrpc_serial_t resp_serial,
+ s64 rtt, u8 nr, s64 avg),
+
+ TP_ARGS(call, why, send_serial, resp_serial, rtt, nr, avg),
+
+ TP_STRUCT__entry(
+ __field(struct rxrpc_call *, call )
+ __field(enum rxrpc_rtt_rx_trace, why )
+ __field(u8, nr )
+ __field(rxrpc_serial_t, send_serial )
+ __field(rxrpc_serial_t, resp_serial )
+ __field(s64, rtt )
+ __field(u64, avg )
+ ),
+
+ TP_fast_assign(
+ __entry->call = call;
+ __entry->why = why;
+ __entry->send_serial = send_serial;
+ __entry->resp_serial = resp_serial;
+ __entry->rtt = rtt;
+ __entry->nr = nr;
+ __entry->avg = avg;
+ ),
+
+ TP_printk("c=%p %s sr=%08x rr=%08x rtt=%lld nr=%u avg=%lld",
+ __entry->call,
+ rxrpc_rtt_rx_traces[__entry->why],
+ __entry->send_serial,
+ __entry->resp_serial,
+ __entry->rtt,
+ __entry->nr,
+ __entry->avg)
+ );
+
#endif /* _TRACE_RXRPC_H */
/* This part must be outside protection */
diff --git a/net/rxrpc/ar-internal.h b/net/rxrpc/ar-internal.h
index dcf54e3fb478..79c671e552c3 100644
--- a/net/rxrpc/ar-internal.h
+++ b/net/rxrpc/ar-internal.h
@@ -258,10 +258,11 @@ struct rxrpc_peer {
/* calculated RTT cache */
#define RXRPC_RTT_CACHE_SIZE 32
- suseconds_t rtt; /* current RTT estimate (in uS) */
- unsigned int rtt_point; /* next entry at which to insert */
- unsigned int rtt_usage; /* amount of cache actually used */
- suseconds_t rtt_cache[RXRPC_RTT_CACHE_SIZE]; /* calculated RTT cache */
+ u64 rtt; /* Current RTT estimate (in nS) */
+ u64 rtt_sum; /* Sum of cache contents */
+ u64 rtt_cache[RXRPC_RTT_CACHE_SIZE]; /* Determined RTT cache */
+ u8 rtt_cursor; /* next entry at which to insert */
+ u8 rtt_usage; /* amount of cache actually used */
};
/*
@@ -657,6 +658,20 @@ enum rxrpc_recvmsg_trace {
extern const char rxrpc_recvmsg_traces[rxrpc_recvmsg__nr_trace][5];
+enum rxrpc_rtt_tx_trace {
+ rxrpc_rtt_tx_ping,
+ rxrpc_rtt_tx__nr_trace
+};
+
+extern const char rxrpc_rtt_tx_traces[rxrpc_rtt_tx__nr_trace][5];
+
+enum rxrpc_rtt_rx_trace {
+ rxrpc_rtt_rx_ping_response,
+ rxrpc_rtt_rx__nr_trace
+};
+
+extern const char rxrpc_rtt_rx_traces[rxrpc_rtt_rx__nr_trace][5];
+
extern const char *const rxrpc_pkts[];
extern const char *rxrpc_acks(u8 reason);
@@ -955,6 +970,8 @@ void rxrpc_reject_packets(struct rxrpc_local *);
*/
void rxrpc_error_report(struct sock *);
void rxrpc_peer_error_distributor(struct work_struct *);
+void rxrpc_peer_add_rtt(struct rxrpc_call *, enum rxrpc_rtt_rx_trace,
+ rxrpc_serial_t, rxrpc_serial_t, ktime_t, ktime_t);
/*
* peer_object.c
diff --git a/net/rxrpc/misc.c b/net/rxrpc/misc.c
index 026e1f2e83ff..6321c23f9a6e 100644
--- a/net/rxrpc/misc.c
+++ b/net/rxrpc/misc.c
@@ -182,3 +182,11 @@ const char rxrpc_recvmsg_traces[rxrpc_recvmsg__nr_trace][5] = {
[rxrpc_recvmsg_to_be_accepted] = "TBAC",
[rxrpc_recvmsg_return] = "RETN",
};
+
+const char rxrpc_rtt_tx_traces[rxrpc_rtt_tx__nr_trace][5] = {
+ [rxrpc_rtt_tx_ping] = "PING",
+};
+
+const char rxrpc_rtt_rx_traces[rxrpc_rtt_rx__nr_trace][5] = {
+ [rxrpc_rtt_rx_ping_response] = "PONG",
+};
diff --git a/net/rxrpc/peer_event.c b/net/rxrpc/peer_event.c
index 18276e7cb9e0..bf13b8470c9a 100644
--- a/net/rxrpc/peer_event.c
+++ b/net/rxrpc/peer_event.c
@@ -305,3 +305,44 @@ void rxrpc_peer_error_distributor(struct work_struct *work)
rxrpc_put_peer(peer);
_leave("");
}
+
+/*
+ * Add RTT information to cache. This is called in softirq mode and has
+ * exclusive access to the peer RTT data.
+ */
+void rxrpc_peer_add_rtt(struct rxrpc_call *call, enum rxrpc_rtt_rx_trace why,
+ rxrpc_serial_t send_serial, rxrpc_serial_t resp_serial,
+ ktime_t send_time, ktime_t resp_time)
+{
+ struct rxrpc_peer *peer = call->peer;
+ s64 rtt;
+ u64 sum = peer->rtt_sum, avg;
+ u8 cursor = peer->rtt_cursor, usage = peer->rtt_usage;
+
+ rtt = ktime_to_ns(ktime_sub(resp_time, send_time));
+ if (rtt < 0)
+ return;
+
+ /* Replace the oldest datum in the RTT buffer */
+ sum -= peer->rtt_cache[cursor];
+ sum += rtt;
+ peer->rtt_cache[cursor] = rtt;
+ peer->rtt_cursor = (cursor + 1) & (RXRPC_RTT_CACHE_SIZE - 1);
+ peer->rtt_sum = sum;
+ if (usage < RXRPC_RTT_CACHE_SIZE) {
+ usage++;
+ peer->rtt_usage = usage;
+ }
+
+ /* Now recalculate the average */
+ if (usage == RXRPC_RTT_CACHE_SIZE) {
+ avg = sum / RXRPC_RTT_CACHE_SIZE;
+ } else {
+ avg = sum;
+ do_div(avg, usage);
+ }
+
+ peer->rtt = avg;
+ trace_rxrpc_rtt_rx(call, why, send_serial, resp_serial, rtt,
+ usage, avg);
+}
^ permalink raw reply related [flat|nested] 11+ messages in thread
* [PATCH net-next 4/9] rxrpc: Send pings to get RTT data [ver #2]
2016-09-22 8:22 [PATCH net-next 0/9] rxrpc: Preparation for slow-start algorithm [ver #2] David Howells
` (2 preceding siblings ...)
2016-09-22 8:22 ` [PATCH net-next 3/9] rxrpc: Add per-peer RTT tracker " David Howells
@ 2016-09-22 8:22 ` David Howells
2016-09-22 8:22 ` [PATCH net-next 5/9] rxrpc: Expedite ping response transmission " David Howells
` (5 subsequent siblings)
9 siblings, 0 replies; 11+ messages in thread
From: David Howells @ 2016-09-22 8:22 UTC (permalink / raw)
To: netdev; +Cc: dhowells, linux-afs, linux-kernel
Send a PING ACK packet to the peer when we get a new incoming call from a
peer we don't have a record for. The PING RESPONSE ACK packet will tell us
the following about the peer:
(1) its receive window size
(2) its MTU sizes
(3) its support for jumbo DATA packets
(4) if it supports slow start (similar to RFC 5681)
(5) an estimate of the RTT
This is necessary because the peer won't normally send us an ACK until it
gets to the Rx phase and we send it a packet, but we would like to know
some of this information before we start sending packets.
A pair of tracepoints are added so that RTT determination can be observed.
Signed-off-by: David Howells <dhowells@redhat.com>
---
net/rxrpc/ar-internal.h | 7 +++++--
net/rxrpc/input.c | 48 ++++++++++++++++++++++++++++++++++++++++++++++-
net/rxrpc/misc.c | 11 ++++++-----
net/rxrpc/output.c | 22 ++++++++++++++++++++++
4 files changed, 80 insertions(+), 8 deletions(-)
diff --git a/net/rxrpc/ar-internal.h b/net/rxrpc/ar-internal.h
index 79c671e552c3..8b47f468eb9d 100644
--- a/net/rxrpc/ar-internal.h
+++ b/net/rxrpc/ar-internal.h
@@ -403,6 +403,7 @@ enum rxrpc_call_flag {
RXRPC_CALL_EXPOSED, /* The call was exposed to the world */
RXRPC_CALL_RX_LAST, /* Received the last packet (at rxtx_top) */
RXRPC_CALL_TX_LAST, /* Last packet in Tx buffer (at rxtx_top) */
+ RXRPC_CALL_PINGING, /* Ping in process */
};
/*
@@ -487,6 +488,8 @@ struct rxrpc_call {
u32 call_id; /* call ID on connection */
u32 cid; /* connection ID plus channel index */
int debug_id; /* debug ID for printks */
+ unsigned short rx_pkt_offset; /* Current recvmsg packet offset */
+ unsigned short rx_pkt_len; /* Current recvmsg packet len */
/* Rx/Tx circular buffer, depending on phase.
*
@@ -530,8 +533,8 @@ struct rxrpc_call {
u16 ackr_skew; /* skew on packet being ACK'd */
rxrpc_serial_t ackr_serial; /* serial of packet being ACK'd */
rxrpc_seq_t ackr_prev_seq; /* previous sequence number received */
- unsigned short rx_pkt_offset; /* Current recvmsg packet offset */
- unsigned short rx_pkt_len; /* Current recvmsg packet len */
+ rxrpc_serial_t ackr_ping; /* Last ping sent */
+ ktime_t ackr_ping_time; /* Time last ping sent */
/* transmission-phase ACK management */
rxrpc_serial_t acks_latest; /* serial number of latest ACK received */
diff --git a/net/rxrpc/input.c b/net/rxrpc/input.c
index aa261df9fc9e..a0a5bd108c9e 100644
--- a/net/rxrpc/input.c
+++ b/net/rxrpc/input.c
@@ -37,6 +37,19 @@ static void rxrpc_proto_abort(const char *why,
}
/*
+ * Ping the other end to fill our RTT cache and to retrieve the rwind
+ * and MTU parameters.
+ */
+static void rxrpc_send_ping(struct rxrpc_call *call, struct sk_buff *skb,
+ int skew)
+{
+ struct rxrpc_skb_priv *sp = rxrpc_skb(skb);
+
+ rxrpc_propose_ACK(call, RXRPC_ACK_PING, skew, sp->hdr.serial,
+ true, true);
+}
+
+/*
* Apply a hard ACK by advancing the Tx window.
*/
static void rxrpc_rotate_tx_window(struct rxrpc_call *call, rxrpc_seq_t to)
@@ -343,6 +356,32 @@ ack:
}
/*
+ * Process a ping response.
+ */
+static void rxrpc_input_ping_response(struct rxrpc_call *call,
+ ktime_t resp_time,
+ rxrpc_serial_t orig_serial,
+ rxrpc_serial_t ack_serial)
+{
+ rxrpc_serial_t ping_serial;
+ ktime_t ping_time;
+
+ ping_time = call->ackr_ping_time;
+ smp_rmb();
+ ping_serial = call->ackr_ping;
+
+ if (!test_bit(RXRPC_CALL_PINGING, &call->flags) ||
+ before(orig_serial, ping_serial))
+ return;
+ clear_bit(RXRPC_CALL_PINGING, &call->flags);
+ if (after(orig_serial, ping_serial))
+ return;
+
+ rxrpc_peer_add_rtt(call, rxrpc_rtt_rx_ping_response,
+ orig_serial, ack_serial, ping_time, resp_time);
+}
+
+/*
* Process the extra information that may be appended to an ACK packet
*/
static void rxrpc_input_ackinfo(struct rxrpc_call *call, struct sk_buff *skb,
@@ -438,6 +477,7 @@ static void rxrpc_input_ack(struct rxrpc_call *call, struct sk_buff *skb,
struct rxrpc_ackinfo info;
u8 acks[RXRPC_MAXACKS];
} buf;
+ rxrpc_serial_t acked_serial;
rxrpc_seq_t first_soft_ack, hard_ack;
int nr_acks, offset;
@@ -449,6 +489,7 @@ static void rxrpc_input_ack(struct rxrpc_call *call, struct sk_buff *skb,
}
sp->offset += sizeof(buf.ack);
+ acked_serial = ntohl(buf.ack.serial);
first_soft_ack = ntohl(buf.ack.firstPacket);
hard_ack = first_soft_ack - 1;
nr_acks = buf.ack.nAcks;
@@ -460,10 +501,14 @@ static void rxrpc_input_ack(struct rxrpc_call *call, struct sk_buff *skb,
ntohs(buf.ack.maxSkew),
first_soft_ack,
ntohl(buf.ack.previousPacket),
- ntohl(buf.ack.serial),
+ acked_serial,
rxrpc_acks(buf.ack.reason),
buf.ack.nAcks);
+ if (buf.ack.reason == RXRPC_ACK_PING_RESPONSE)
+ rxrpc_input_ping_response(call, skb->tstamp, acked_serial,
+ sp->hdr.serial);
+
if (buf.ack.reason == RXRPC_ACK_PING) {
_proto("Rx ACK %%%u PING Request", sp->hdr.serial);
rxrpc_propose_ACK(call, RXRPC_ACK_PING_RESPONSE,
@@ -830,6 +875,7 @@ void rxrpc_data_ready(struct sock *udp_sk)
rcu_read_unlock();
goto reject_packet;
}
+ rxrpc_send_ping(call, skb, skew);
}
rxrpc_input_call_packet(call, skb, skew);
diff --git a/net/rxrpc/misc.c b/net/rxrpc/misc.c
index 6321c23f9a6e..56e668352fc7 100644
--- a/net/rxrpc/misc.c
+++ b/net/rxrpc/misc.c
@@ -83,11 +83,12 @@ const s8 rxrpc_ack_priority[] = {
[RXRPC_ACK_DELAY] = 1,
[RXRPC_ACK_REQUESTED] = 2,
[RXRPC_ACK_IDLE] = 3,
- [RXRPC_ACK_PING_RESPONSE] = 4,
- [RXRPC_ACK_DUPLICATE] = 5,
- [RXRPC_ACK_OUT_OF_SEQUENCE] = 6,
- [RXRPC_ACK_EXCEEDS_WINDOW] = 7,
- [RXRPC_ACK_NOSPACE] = 8,
+ [RXRPC_ACK_DUPLICATE] = 4,
+ [RXRPC_ACK_OUT_OF_SEQUENCE] = 5,
+ [RXRPC_ACK_EXCEEDS_WINDOW] = 6,
+ [RXRPC_ACK_NOSPACE] = 7,
+ [RXRPC_ACK_PING_RESPONSE] = 8,
+ [RXRPC_ACK_PING] = 9,
};
const char *rxrpc_acks(u8 reason)
diff --git a/net/rxrpc/output.c b/net/rxrpc/output.c
index 817fb0e82d6a..0d89cd3f2c01 100644
--- a/net/rxrpc/output.c
+++ b/net/rxrpc/output.c
@@ -57,6 +57,9 @@ static size_t rxrpc_fill_out_ack(struct rxrpc_call *call,
pkt->ack.reason = call->ackr_reason;
pkt->ack.nAcks = top - hard_ack;
+ if (pkt->ack.reason == RXRPC_ACK_PING)
+ pkt->whdr.flags |= RXRPC_REQUEST_ACK;
+
if (after(top, hard_ack)) {
seq = hard_ack + 1;
do {
@@ -97,6 +100,7 @@ int rxrpc_send_call_packet(struct rxrpc_call *call, u8 type)
struct kvec iov[2];
rxrpc_serial_t serial;
size_t len, n;
+ bool ping = false;
int ioc, ret;
u32 abort_code;
@@ -147,6 +151,7 @@ int rxrpc_send_call_packet(struct rxrpc_call *call, u8 type)
ret = 0;
goto out;
}
+ ping = (call->ackr_reason == RXRPC_ACK_PING);
n = rxrpc_fill_out_ack(call, pkt);
call->ackr_reason = 0;
@@ -183,12 +188,29 @@ int rxrpc_send_call_packet(struct rxrpc_call *call, u8 type)
goto out;
}
+ if (ping) {
+ call->ackr_ping = serial;
+ smp_wmb();
+ /* We need to stick a time in before we send the packet in case
+ * the reply gets back before kernel_sendmsg() completes - but
+ * asking UDP to send the packet can take a relatively long
+ * time, so we update the time after, on the assumption that
+ * the packet transmission is more likely to happen towards the
+ * end of the kernel_sendmsg() call.
+ */
+ call->ackr_ping_time = ktime_get_real();
+ set_bit(RXRPC_CALL_PINGING, &call->flags);
+ trace_rxrpc_rtt_tx(call, rxrpc_rtt_tx_ping, serial);
+ }
ret = kernel_sendmsg(conn->params.local->socket,
&msg, iov, ioc, len);
+ if (ping)
+ call->ackr_ping_time = ktime_get_real();
if (ret < 0 && call->state < RXRPC_CALL_COMPLETE) {
switch (type) {
case RXRPC_PACKET_TYPE_ACK:
+ clear_bit(RXRPC_CALL_PINGING, &call->flags);
rxrpc_propose_ACK(call, pkt->ack.reason,
ntohs(pkt->ack.maxSkew),
ntohl(pkt->ack.serial),
^ permalink raw reply related [flat|nested] 11+ messages in thread
* [PATCH net-next 5/9] rxrpc: Expedite ping response transmission [ver #2]
2016-09-22 8:22 [PATCH net-next 0/9] rxrpc: Preparation for slow-start algorithm [ver #2] David Howells
` (3 preceding siblings ...)
2016-09-22 8:22 ` [PATCH net-next 4/9] rxrpc: Send pings to get RTT data " David Howells
@ 2016-09-22 8:22 ` David Howells
2016-09-22 8:22 ` [PATCH net-next 6/9] rxrpc: Add ktime_sub_ms() " David Howells
` (4 subsequent siblings)
9 siblings, 0 replies; 11+ messages in thread
From: David Howells @ 2016-09-22 8:22 UTC (permalink / raw)
To: netdev; +Cc: dhowells, linux-afs, linux-kernel
Expedite the transmission of a response to a PING ACK by sending it from
sendmsg if one is pending. We're most likely to see a PING ACK during the
client call Tx phase as the other side may use it to determine a number of
parameters, such as the client's receive window size, the RTT and whether
the client is doing slow start (similar to RFC5681).
If we don't expedite it, it's left to the background processing thread to
transmit.
Signed-off-by: David Howells <dhowells@redhat.com>
---
net/rxrpc/sendmsg.c | 4 ++++
1 file changed, 4 insertions(+)
diff --git a/net/rxrpc/sendmsg.c b/net/rxrpc/sendmsg.c
index 814b17f23971..3c969de3ef05 100644
--- a/net/rxrpc/sendmsg.c
+++ b/net/rxrpc/sendmsg.c
@@ -180,6 +180,10 @@ static int rxrpc_send_data(struct rxrpc_sock *rx,
copied = 0;
do {
+ /* Check to see if there's a ping ACK to reply to. */
+ if (call->ackr_reason == RXRPC_ACK_PING_RESPONSE)
+ rxrpc_send_call_packet(call, RXRPC_PACKET_TYPE_ACK);
+
if (!skb) {
size_t size, chunk, max, space;
^ permalink raw reply related [flat|nested] 11+ messages in thread
* [PATCH net-next 6/9] rxrpc: Add ktime_sub_ms() [ver #2]
2016-09-22 8:22 [PATCH net-next 0/9] rxrpc: Preparation for slow-start algorithm [ver #2] David Howells
` (4 preceding siblings ...)
2016-09-22 8:22 ` [PATCH net-next 5/9] rxrpc: Expedite ping response transmission " David Howells
@ 2016-09-22 8:22 ` David Howells
2016-09-22 8:22 ` [PATCH net-next 7/9] rxrpc: Obtain RTT data by requesting ACKs on DATA packets " David Howells
` (3 subsequent siblings)
9 siblings, 0 replies; 11+ messages in thread
From: David Howells @ 2016-09-22 8:22 UTC (permalink / raw)
To: netdev; +Cc: dhowells, linux-afs, linux-kernel
Add a ktime_sub_ms() to go with ktime_add_ms() and co. for use in AF_RXRPC
RTT determination.
Signed-off-by: David Howells <dhowells@redhat.com>
---
include/linux/ktime.h | 5 +++++
1 file changed, 5 insertions(+)
diff --git a/include/linux/ktime.h b/include/linux/ktime.h
index 2b6a204bd8d4..aa118bad1407 100644
--- a/include/linux/ktime.h
+++ b/include/linux/ktime.h
@@ -231,6 +231,11 @@ static inline ktime_t ktime_sub_us(const ktime_t kt, const u64 usec)
return ktime_sub_ns(kt, usec * NSEC_PER_USEC);
}
+static inline ktime_t ktime_sub_ms(const ktime_t kt, const u64 msec)
+{
+ return ktime_sub_ns(kt, msec * NSEC_PER_MSEC);
+}
+
extern ktime_t ktime_add_safe(const ktime_t lhs, const ktime_t rhs);
/**
^ permalink raw reply related [flat|nested] 11+ messages in thread
* [PATCH net-next 7/9] rxrpc: Obtain RTT data by requesting ACKs on DATA packets [ver #2]
2016-09-22 8:22 [PATCH net-next 0/9] rxrpc: Preparation for slow-start algorithm [ver #2] David Howells
` (5 preceding siblings ...)
2016-09-22 8:22 ` [PATCH net-next 6/9] rxrpc: Add ktime_sub_ms() " David Howells
@ 2016-09-22 8:22 ` David Howells
2016-09-22 8:22 ` [PATCH net-next 8/9] rxrpc: Reduce the number of ACK-Requests sent " David Howells
` (2 subsequent siblings)
9 siblings, 0 replies; 11+ messages in thread
From: David Howells @ 2016-09-22 8:22 UTC (permalink / raw)
To: netdev; +Cc: dhowells, linux-afs, linux-kernel
In addition to sending a PING ACK to gain RTT data, we can set the
RXRPC_REQUEST_ACK flag on a DATA packet and get a REQUESTED-ACK ACK. The
ACK packet contains the serial number of the packet it is in response to,
so we can look through the Tx buffer for a matching DATA packet.
This requires that the data packets be stamped with the time of
transmission as a ktime rather than having the resend_at time in jiffies.
This further requires the resend code to do the resend determination in
ktimes and convert to jiffies to set the timer.
Signed-off-by: David Howells <dhowells@redhat.com>
---
net/rxrpc/ar-internal.h | 7 +++----
net/rxrpc/call_event.c | 19 +++++++++----------
net/rxrpc/input.c | 35 +++++++++++++++++++++++++++++++++++
net/rxrpc/misc.c | 6 ++++--
net/rxrpc/output.c | 7 +++++--
net/rxrpc/sendmsg.c | 1 -
net/rxrpc/sysctl.c | 2 +-
7 files changed, 57 insertions(+), 20 deletions(-)
diff --git a/net/rxrpc/ar-internal.h b/net/rxrpc/ar-internal.h
index 8b47f468eb9d..1c4597b2c6cd 100644
--- a/net/rxrpc/ar-internal.h
+++ b/net/rxrpc/ar-internal.h
@@ -142,10 +142,7 @@ struct rxrpc_host_header {
*/
struct rxrpc_skb_priv {
union {
- unsigned long resend_at; /* time in jiffies at which to resend */
- struct {
- u8 nr_jumbo; /* Number of jumbo subpackets */
- };
+ u8 nr_jumbo; /* Number of jumbo subpackets */
};
union {
unsigned int offset; /* offset into buffer of next read */
@@ -663,6 +660,7 @@ extern const char rxrpc_recvmsg_traces[rxrpc_recvmsg__nr_trace][5];
enum rxrpc_rtt_tx_trace {
rxrpc_rtt_tx_ping,
+ rxrpc_rtt_tx_data,
rxrpc_rtt_tx__nr_trace
};
@@ -670,6 +668,7 @@ extern const char rxrpc_rtt_tx_traces[rxrpc_rtt_tx__nr_trace][5];
enum rxrpc_rtt_rx_trace {
rxrpc_rtt_rx_ping_response,
+ rxrpc_rtt_rx_requested_ack,
rxrpc_rtt_rx__nr_trace
};
diff --git a/net/rxrpc/call_event.c b/net/rxrpc/call_event.c
index 34ad967f2d81..adb2ec61e21f 100644
--- a/net/rxrpc/call_event.c
+++ b/net/rxrpc/call_event.c
@@ -142,12 +142,14 @@ static void rxrpc_resend(struct rxrpc_call *call)
struct rxrpc_skb_priv *sp;
struct sk_buff *skb;
rxrpc_seq_t cursor, seq, top;
- unsigned long resend_at, now;
+ ktime_t now = ktime_get_real(), max_age, oldest, resend_at;
int ix;
u8 annotation, anno_type;
_enter("{%d,%d}", call->tx_hard_ack, call->tx_top);
+ max_age = ktime_sub_ms(now, rxrpc_resend_timeout);
+
spin_lock_bh(&call->lock);
cursor = call->tx_hard_ack;
@@ -160,8 +162,7 @@ static void rxrpc_resend(struct rxrpc_call *call)
* the packets in the Tx buffer we're going to resend and what the new
* resend timeout will be.
*/
- now = jiffies;
- resend_at = now + rxrpc_resend_timeout;
+ oldest = now;
for (seq = cursor + 1; before_eq(seq, top); seq++) {
ix = seq & RXRPC_RXTX_BUFF_MASK;
annotation = call->rxtx_annotations[ix];
@@ -175,9 +176,9 @@ static void rxrpc_resend(struct rxrpc_call *call)
sp = rxrpc_skb(skb);
if (anno_type == RXRPC_TX_ANNO_UNACK) {
- if (time_after(sp->resend_at, now)) {
- if (time_before(sp->resend_at, resend_at))
- resend_at = sp->resend_at;
+ if (ktime_after(skb->tstamp, max_age)) {
+ if (ktime_before(skb->tstamp, oldest))
+ oldest = skb->tstamp;
continue;
}
}
@@ -186,7 +187,8 @@ static void rxrpc_resend(struct rxrpc_call *call)
call->rxtx_annotations[ix] = RXRPC_TX_ANNO_RETRANS | annotation;
}
- call->resend_at = resend_at;
+ resend_at = ktime_sub(ktime_add_ns(oldest, rxrpc_resend_timeout), now);
+ call->resend_at = jiffies + nsecs_to_jiffies(ktime_to_ns(resend_at));
/* Now go through the Tx window and perform the retransmissions. We
* have to drop the lock for each send. If an ACK comes in whilst the
@@ -205,15 +207,12 @@ static void rxrpc_resend(struct rxrpc_call *call)
spin_unlock_bh(&call->lock);
if (rxrpc_send_data_packet(call, skb) < 0) {
- call->resend_at = now + 2;
rxrpc_free_skb(skb, rxrpc_skb_tx_freed);
return;
}
if (rxrpc_is_client_call(call))
rxrpc_expose_client_call(call);
- sp = rxrpc_skb(skb);
- sp->resend_at = now + rxrpc_resend_timeout;
rxrpc_free_skb(skb, rxrpc_skb_tx_freed);
spin_lock_bh(&call->lock);
diff --git a/net/rxrpc/input.c b/net/rxrpc/input.c
index a0a5bd108c9e..c121949de3c8 100644
--- a/net/rxrpc/input.c
+++ b/net/rxrpc/input.c
@@ -356,6 +356,38 @@ ack:
}
/*
+ * Process a requested ACK.
+ */
+static void rxrpc_input_requested_ack(struct rxrpc_call *call,
+ ktime_t resp_time,
+ rxrpc_serial_t orig_serial,
+ rxrpc_serial_t ack_serial)
+{
+ struct rxrpc_skb_priv *sp;
+ struct sk_buff *skb;
+ ktime_t sent_at;
+ int ix;
+
+ for (ix = 0; ix < RXRPC_RXTX_BUFF_SIZE; ix++) {
+ skb = call->rxtx_buffer[ix];
+ if (!skb)
+ continue;
+
+ sp = rxrpc_skb(skb);
+ if (sp->hdr.serial != orig_serial)
+ continue;
+ smp_rmb();
+ sent_at = skb->tstamp;
+ goto found;
+ }
+ return;
+
+found:
+ rxrpc_peer_add_rtt(call, rxrpc_rtt_rx_requested_ack,
+ orig_serial, ack_serial, sent_at, resp_time);
+}
+
+/*
* Process a ping response.
*/
static void rxrpc_input_ping_response(struct rxrpc_call *call,
@@ -508,6 +540,9 @@ static void rxrpc_input_ack(struct rxrpc_call *call, struct sk_buff *skb,
if (buf.ack.reason == RXRPC_ACK_PING_RESPONSE)
rxrpc_input_ping_response(call, skb->tstamp, acked_serial,
sp->hdr.serial);
+ if (buf.ack.reason == RXRPC_ACK_REQUESTED)
+ rxrpc_input_requested_ack(call, skb->tstamp, acked_serial,
+ sp->hdr.serial);
if (buf.ack.reason == RXRPC_ACK_PING) {
_proto("Rx ACK %%%u PING Request", sp->hdr.serial);
diff --git a/net/rxrpc/misc.c b/net/rxrpc/misc.c
index 56e668352fc7..0d425e707f22 100644
--- a/net/rxrpc/misc.c
+++ b/net/rxrpc/misc.c
@@ -68,9 +68,9 @@ unsigned int rxrpc_rx_mtu = 5692;
unsigned int rxrpc_rx_jumbo_max = 4;
/*
- * Time till packet resend (in jiffies).
+ * Time till packet resend (in milliseconds).
*/
-unsigned int rxrpc_resend_timeout = 4 * HZ;
+unsigned int rxrpc_resend_timeout = 4 * 1000;
const char *const rxrpc_pkts[] = {
"?00",
@@ -186,8 +186,10 @@ const char rxrpc_recvmsg_traces[rxrpc_recvmsg__nr_trace][5] = {
const char rxrpc_rtt_tx_traces[rxrpc_rtt_tx__nr_trace][5] = {
[rxrpc_rtt_tx_ping] = "PING",
+ [rxrpc_rtt_tx_data] = "DATA",
};
const char rxrpc_rtt_rx_traces[rxrpc_rtt_rx__nr_trace][5] = {
[rxrpc_rtt_rx_ping_response] = "PONG",
+ [rxrpc_rtt_rx_requested_ack] = "RACK",
};
diff --git a/net/rxrpc/output.c b/net/rxrpc/output.c
index 0d89cd3f2c01..db01fbb70d23 100644
--- a/net/rxrpc/output.c
+++ b/net/rxrpc/output.c
@@ -300,9 +300,12 @@ int rxrpc_send_data_packet(struct rxrpc_call *call, struct sk_buff *skb)
goto send_fragmentable;
done:
- if (ret == 0) {
- sp->resend_at = jiffies + rxrpc_resend_timeout;
+ if (ret >= 0) {
+ skb->tstamp = ktime_get_real();
+ smp_wmb();
sp->hdr.serial = serial;
+ if (whdr.flags & RXRPC_REQUEST_ACK)
+ trace_rxrpc_rtt_tx(call, rxrpc_rtt_tx_data, serial);
}
_leave(" = %d [%u]", ret, call->peer->maxdata);
return ret;
diff --git a/net/rxrpc/sendmsg.c b/net/rxrpc/sendmsg.c
index 3c969de3ef05..607223f4f871 100644
--- a/net/rxrpc/sendmsg.c
+++ b/net/rxrpc/sendmsg.c
@@ -137,7 +137,6 @@ static void rxrpc_queue_packet(struct rxrpc_call *call, struct sk_buff *skb,
if (seq == 1 && rxrpc_is_client_call(call))
rxrpc_expose_client_call(call);
- sp->resend_at = jiffies + rxrpc_resend_timeout;
ret = rxrpc_send_data_packet(call, skb);
if (ret < 0) {
_debug("need instant resend %d", ret);
diff --git a/net/rxrpc/sysctl.c b/net/rxrpc/sysctl.c
index a03c61c672f5..13d1df03ebac 100644
--- a/net/rxrpc/sysctl.c
+++ b/net/rxrpc/sysctl.c
@@ -59,7 +59,7 @@ static struct ctl_table rxrpc_sysctl_table[] = {
.data = &rxrpc_resend_timeout,
.maxlen = sizeof(unsigned int),
.mode = 0644,
- .proc_handler = proc_dointvec_ms_jiffies,
+ .proc_handler = proc_dointvec,
.extra1 = (void *)&one,
},
{
^ permalink raw reply related [flat|nested] 11+ messages in thread
* [PATCH net-next 8/9] rxrpc: Reduce the number of ACK-Requests sent [ver #2]
2016-09-22 8:22 [PATCH net-next 0/9] rxrpc: Preparation for slow-start algorithm [ver #2] David Howells
` (6 preceding siblings ...)
2016-09-22 8:22 ` [PATCH net-next 7/9] rxrpc: Obtain RTT data by requesting ACKs on DATA packets " David Howells
@ 2016-09-22 8:22 ` David Howells
2016-09-22 8:23 ` [PATCH net-next 9/9] rxrpc: Reduce the number of PING ACKs " David Howells
2016-09-22 12:15 ` [PATCH net-next 0/9] rxrpc: Preparation for slow-start algorithm " David Miller
9 siblings, 0 replies; 11+ messages in thread
From: David Howells @ 2016-09-22 8:22 UTC (permalink / raw)
To: netdev; +Cc: dhowells, linux-afs, linux-kernel
Reduce the number of ACK-Requests we set on DATA packets that we're sending
to reduce network traffic. We set the flag on odd-numbered DATA packets to
start off the RTT cache until we have at least three entries in it and then
probe once per second thereafter to keep it topped up.
This could be made tunable in future.
Note that from this point, the RXRPC_REQUEST_ACK flag is set on DATA
packets as we transmit them and not stored statically in the sk_buff.
Signed-off-by: David Howells <dhowells@redhat.com>
---
net/rxrpc/ar-internal.h | 1 +
net/rxrpc/output.c | 13 +++++++++++--
net/rxrpc/peer_object.c | 1 +
net/rxrpc/sendmsg.c | 2 --
4 files changed, 13 insertions(+), 4 deletions(-)
diff --git a/net/rxrpc/ar-internal.h b/net/rxrpc/ar-internal.h
index 1c4597b2c6cd..b13754a6dd7a 100644
--- a/net/rxrpc/ar-internal.h
+++ b/net/rxrpc/ar-internal.h
@@ -255,6 +255,7 @@ struct rxrpc_peer {
/* calculated RTT cache */
#define RXRPC_RTT_CACHE_SIZE 32
+ ktime_t rtt_last_req; /* Time of last RTT request */
u64 rtt; /* Current RTT estimate (in nS) */
u64 rtt_sum; /* Sum of cache contents */
u64 rtt_cache[RXRPC_RTT_CACHE_SIZE]; /* Determined RTT cache */
diff --git a/net/rxrpc/output.c b/net/rxrpc/output.c
index db01fbb70d23..282cb1e36d06 100644
--- a/net/rxrpc/output.c
+++ b/net/rxrpc/output.c
@@ -270,6 +270,12 @@ int rxrpc_send_data_packet(struct rxrpc_call *call, struct sk_buff *skb)
msg.msg_controllen = 0;
msg.msg_flags = 0;
+ /* If our RTT cache needs working on, request an ACK. */
+ if ((call->peer->rtt_usage < 3 && sp->hdr.seq & 1) ||
+ ktime_before(ktime_add_ms(call->peer->rtt_last_req, 1000),
+ ktime_get_real()))
+ whdr.flags |= RXRPC_REQUEST_ACK;
+
if (IS_ENABLED(CONFIG_AF_RXRPC_INJECT_LOSS)) {
static int lose;
if ((lose++ & 7) == 7) {
@@ -301,11 +307,14 @@ int rxrpc_send_data_packet(struct rxrpc_call *call, struct sk_buff *skb)
done:
if (ret >= 0) {
- skb->tstamp = ktime_get_real();
+ ktime_t now = ktime_get_real();
+ skb->tstamp = now;
smp_wmb();
sp->hdr.serial = serial;
- if (whdr.flags & RXRPC_REQUEST_ACK)
+ if (whdr.flags & RXRPC_REQUEST_ACK) {
+ call->peer->rtt_last_req = now;
trace_rxrpc_rtt_tx(call, rxrpc_rtt_tx_data, serial);
+ }
}
_leave(" = %d [%u]", ret, call->peer->maxdata);
return ret;
diff --git a/net/rxrpc/peer_object.c b/net/rxrpc/peer_object.c
index f3e5766910fd..941b724d523b 100644
--- a/net/rxrpc/peer_object.c
+++ b/net/rxrpc/peer_object.c
@@ -244,6 +244,7 @@ static void rxrpc_init_peer(struct rxrpc_peer *peer, unsigned long hash_key)
peer->hash_key = hash_key;
rxrpc_assess_MTU_size(peer);
peer->mtu = peer->if_mtu;
+ peer->rtt_last_req = ktime_get_real();
switch (peer->srx.transport.family) {
case AF_INET:
diff --git a/net/rxrpc/sendmsg.c b/net/rxrpc/sendmsg.c
index 607223f4f871..ca7c3be60ad2 100644
--- a/net/rxrpc/sendmsg.c
+++ b/net/rxrpc/sendmsg.c
@@ -299,8 +299,6 @@ static int rxrpc_send_data(struct rxrpc_sock *rx,
else if (call->tx_top - call->tx_hard_ack <
call->tx_winsize)
sp->hdr.flags |= RXRPC_MORE_PACKETS;
- if (seq & 1)
- sp->hdr.flags |= RXRPC_REQUEST_ACK;
ret = conn->security->secure_packet(
call, skb, skb->mark, skb->head);
^ permalink raw reply related [flat|nested] 11+ messages in thread
* [PATCH net-next 9/9] rxrpc: Reduce the number of PING ACKs sent [ver #2]
2016-09-22 8:22 [PATCH net-next 0/9] rxrpc: Preparation for slow-start algorithm [ver #2] David Howells
` (7 preceding siblings ...)
2016-09-22 8:22 ` [PATCH net-next 8/9] rxrpc: Reduce the number of ACK-Requests sent " David Howells
@ 2016-09-22 8:23 ` David Howells
2016-09-22 12:15 ` [PATCH net-next 0/9] rxrpc: Preparation for slow-start algorithm " David Miller
9 siblings, 0 replies; 11+ messages in thread
From: David Howells @ 2016-09-22 8:23 UTC (permalink / raw)
To: netdev; +Cc: dhowells, linux-afs, linux-kernel
We don't want to send a PING ACK for every new incoming call as that just
adds to the network traffic. Instead, we send a PING ACK to the first
three that we receive and then once per second thereafter.
This could probably be made adjustable in future.
Signed-off-by: David Howells <dhowells@redhat.com>
---
net/rxrpc/call_event.c | 2 +-
net/rxrpc/input.c | 7 +++++--
2 files changed, 6 insertions(+), 3 deletions(-)
diff --git a/net/rxrpc/call_event.c b/net/rxrpc/call_event.c
index adb2ec61e21f..6e2ea8f4ae75 100644
--- a/net/rxrpc/call_event.c
+++ b/net/rxrpc/call_event.c
@@ -142,7 +142,7 @@ static void rxrpc_resend(struct rxrpc_call *call)
struct rxrpc_skb_priv *sp;
struct sk_buff *skb;
rxrpc_seq_t cursor, seq, top;
- ktime_t now = ktime_get_real(), max_age, oldest, resend_at;
+ ktime_t now = ktime_get_real(), max_age, oldest, resend_at;
int ix;
u8 annotation, anno_type;
diff --git a/net/rxrpc/input.c b/net/rxrpc/input.c
index c121949de3c8..cbb5d53f09d7 100644
--- a/net/rxrpc/input.c
+++ b/net/rxrpc/input.c
@@ -44,9 +44,12 @@ static void rxrpc_send_ping(struct rxrpc_call *call, struct sk_buff *skb,
int skew)
{
struct rxrpc_skb_priv *sp = rxrpc_skb(skb);
+ ktime_t now = skb->tstamp;
- rxrpc_propose_ACK(call, RXRPC_ACK_PING, skew, sp->hdr.serial,
- true, true);
+ if (call->peer->rtt_usage < 3 ||
+ ktime_before(ktime_add_ms(call->peer->rtt_last_req, 1000), now))
+ rxrpc_propose_ACK(call, RXRPC_ACK_PING, skew, sp->hdr.serial,
+ true, true);
}
/*
^ permalink raw reply related [flat|nested] 11+ messages in thread
* Re: [PATCH net-next 0/9] rxrpc: Preparation for slow-start algorithm [ver #2]
2016-09-22 8:22 [PATCH net-next 0/9] rxrpc: Preparation for slow-start algorithm [ver #2] David Howells
` (8 preceding siblings ...)
2016-09-22 8:23 ` [PATCH net-next 9/9] rxrpc: Reduce the number of PING ACKs " David Howells
@ 2016-09-22 12:15 ` David Miller
9 siblings, 0 replies; 11+ messages in thread
From: David Miller @ 2016-09-22 12:15 UTC (permalink / raw)
To: dhowells; +Cc: netdev, linux-afs, linux-kernel
From: David Howells <dhowells@redhat.com>
Date: Thu, 22 Sep 2016 09:22:00 +0100
> Tagged thusly:
>
> git://git.kernel.org/pub/scm/linux/kernel/git/dhowells/linux-fs.git
> rxrpc-rewrite-20160922-v2
Pulled, thanks David.
^ permalink raw reply [flat|nested] 11+ messages in thread
end of thread, other threads:[~2016-09-22 12:15 UTC | newest]
Thread overview: 11+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2016-09-22 8:22 [PATCH net-next 0/9] rxrpc: Preparation for slow-start algorithm [ver #2] David Howells
2016-09-22 8:22 ` [PATCH net-next 1/9] rxrpc: Don't store the rxrpc header in the Tx queue sk_buffs " David Howells
2016-09-22 8:22 ` [PATCH net-next 2/9] rxrpc: Add re-sent Tx annotation " David Howells
2016-09-22 8:22 ` [PATCH net-next 3/9] rxrpc: Add per-peer RTT tracker " David Howells
2016-09-22 8:22 ` [PATCH net-next 4/9] rxrpc: Send pings to get RTT data " David Howells
2016-09-22 8:22 ` [PATCH net-next 5/9] rxrpc: Expedite ping response transmission " David Howells
2016-09-22 8:22 ` [PATCH net-next 6/9] rxrpc: Add ktime_sub_ms() " David Howells
2016-09-22 8:22 ` [PATCH net-next 7/9] rxrpc: Obtain RTT data by requesting ACKs on DATA packets " David Howells
2016-09-22 8:22 ` [PATCH net-next 8/9] rxrpc: Reduce the number of ACK-Requests sent " David Howells
2016-09-22 8:23 ` [PATCH net-next 9/9] rxrpc: Reduce the number of PING ACKs " David Howells
2016-09-22 12:15 ` [PATCH net-next 0/9] rxrpc: Preparation for slow-start algorithm " David Miller
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