* [PATCH V5 1/1] hv_netvsc: Use the xmit_more skb flag to optimize signaling the host
@ 2015-05-11 4:08 K. Y. Srinivasan
2015-05-11 5:58 ` Joe Perches
0 siblings, 1 reply; 4+ messages in thread
From: K. Y. Srinivasan @ 2015-05-11 4:08 UTC (permalink / raw)
To: davem, netdev, linux-kernel, devel, olaf, apw, jasowang; +Cc: K. Y. Srinivasan
Based on the information given to this driver (via the xmit_more skb flag),
we can defer signaling the host if more packets are on the way. This will help
make the host more efficient since it can potentially process a larger batch of
packets. Implement this optimization.
Signed-off-by: K. Y. Srinivasan <kys@microsoft.com>
---
v2: Fixed up indentation based on feedback from David Miller.
v3,v4: If the queue could be stopped, deal with that condition: Eric Dumazet <eric.dumazet@gmail.com>
v5: Fixed up indentation based on feedback from David Miller.
drivers/net/hyperv/netvsc.c | 41 +++++++++++++++++++++++++++--------------
1 files changed, 27 insertions(+), 14 deletions(-)
diff --git a/drivers/net/hyperv/netvsc.c b/drivers/net/hyperv/netvsc.c
index ea091bc..7fdf3e8 100644
--- a/drivers/net/hyperv/netvsc.c
+++ b/drivers/net/hyperv/netvsc.c
@@ -743,6 +743,8 @@ static inline int netvsc_send_pkt(
u64 req_id;
int ret;
struct hv_page_buffer *pgbuf;
+ u32 vmbus_flags = VMBUS_DATA_PACKET_FLAG_COMPLETION_REQUESTED;
+ u32 ring_avail = hv_ringbuf_avail_percent(&out_channel->outbound);
nvmsg.hdr.msg_type = NVSP_MSG1_TYPE_SEND_RNDIS_PKT;
if (packet->is_data_pkt) {
@@ -769,30 +771,41 @@ static inline int netvsc_send_pkt(
if (out_channel->rescind)
return -ENODEV;
+ /*
+ * It is possible that once we successfully place this packet
+ * on the ringbuffer, we may stop the queue. In that case, we want
+ * to notify the host independent of the xmit_more flag. We don't
+ * need to be precise here; in the worst case we may signal the host
+ * unnecessarily.
+ */
+ if (ring_avail < (RING_AVAIL_PERCENT_LOWATER + 1))
+ packet->xmit_more = false;
+
if (packet->page_buf_cnt) {
pgbuf = packet->cp_partial ? packet->page_buf +
packet->rmsg_pgcnt : packet->page_buf;
- ret = vmbus_sendpacket_pagebuffer(out_channel,
- pgbuf,
- packet->page_buf_cnt,
- &nvmsg,
- sizeof(struct nvsp_message),
- req_id);
+ ret = vmbus_sendpacket_pagebuffer_ctl(out_channel,
+ pgbuf,
+ packet->page_buf_cnt,
+ &nvmsg,
+ sizeof(struct
+ nvsp_message),
+ req_id,
+ vmbus_flags,
+ !packet->xmit_more);
} else {
- ret = vmbus_sendpacket(
- out_channel, &nvmsg,
- sizeof(struct nvsp_message),
- req_id,
- VM_PKT_DATA_INBAND,
- VMBUS_DATA_PACKET_FLAG_COMPLETION_REQUESTED);
+ ret = vmbus_sendpacket_ctl(out_channel, &nvmsg,
+ sizeof(struct nvsp_message),
+ req_id,
+ VM_PKT_DATA_INBAND,
+ vmbus_flags, !packet->xmit_more);
}
if (ret == 0) {
atomic_inc(&net_device->num_outstanding_sends);
atomic_inc(&net_device->queue_sends[q_idx]);
- if (hv_ringbuf_avail_percent(&out_channel->outbound) <
- RING_AVAIL_PERCENT_LOWATER) {
+ if (ring_avail < RING_AVAIL_PERCENT_LOWATER) {
netif_tx_stop_queue(netdev_get_tx_queue(
ndev, q_idx));
--
1.7.4.1
^ permalink raw reply related [flat|nested] 4+ messages in thread
* Re: [PATCH V5 1/1] hv_netvsc: Use the xmit_more skb flag to optimize signaling the host
2015-05-11 4:08 [PATCH V5 1/1] hv_netvsc: Use the xmit_more skb flag to optimize signaling the host K. Y. Srinivasan
@ 2015-05-11 5:58 ` Joe Perches
2015-05-11 8:59 ` KY Srinivasan
0 siblings, 1 reply; 4+ messages in thread
From: Joe Perches @ 2015-05-11 5:58 UTC (permalink / raw)
To: K. Y. Srinivasan; +Cc: davem, netdev, linux-kernel, devel, olaf, apw, jasowang
On Sun, 2015-05-10 at 21:08 -0700, K. Y. Srinivasan wrote:
> Based on the information given to this driver (via the xmit_more skb flag),
> we can defer signaling the host if more packets are on the way. This will help
> make the host more efficient since it can potentially process a larger batch of
> packets. Implement this optimization.
trivia:
I think that indirecting VMBUS_DATA_PACKET_FLAG_COMPLETTION_REQUESTED
into a non-const temporary isn't very useful.
Whenever overly long identifiers like VMBUS_<FOO> is used,
I think that it'd be better to use it directly and ignore
80 column warnings.
Same with the "sizeof(struct nvsp_message)" on two lines.
> diff --git a/drivers/net/hyperv/netvsc.c b/drivers/net/hyperv/netvsc.c
[]
> @@ -743,6 +743,8 @@ static inline int netvsc_send_pkt(
> u64 req_id;
> int ret;
> struct hv_page_buffer *pgbuf;
> + u32 vmbus_flags = VMBUS_DATA_PACKET_FLAG_COMPLETION_REQUESTED;
> + u32 ring_avail = hv_ringbuf_avail_percent(&out_channel->outbound);
[]
> @@ -769,30 +771,41 @@ static inline int netvsc_send_pkt(
[]
> + ret = vmbus_sendpacket_pagebuffer_ctl(out_channel,
> + pgbuf,
> + packet->page_buf_cnt,
> + &nvmsg,
> + sizeof(struct
> + nvsp_message),
> + req_id,
> + vmbus_flags,
> + !packet->xmit_more);
[]
> netif_tx_stop_queue(netdev_get_tx_queue(
> ndev, q_idx));
This could be on one line too.
^ permalink raw reply [flat|nested] 4+ messages in thread
* RE: [PATCH V5 1/1] hv_netvsc: Use the xmit_more skb flag to optimize signaling the host
2015-05-11 5:58 ` Joe Perches
@ 2015-05-11 8:59 ` KY Srinivasan
2015-05-11 14:41 ` David Miller
0 siblings, 1 reply; 4+ messages in thread
From: KY Srinivasan @ 2015-05-11 8:59 UTC (permalink / raw)
To: Joe Perches; +Cc: davem, netdev, linux-kernel, devel, olaf, apw, jasowang
> -----Original Message-----
> From: Joe Perches [mailto:joe@perches.com]
> Sent: Sunday, May 10, 2015 10:58 PM
> To: KY Srinivasan
> Cc: davem@davemloft.net; netdev@vger.kernel.org; linux-
> kernel@vger.kernel.org; devel@linuxdriverproject.org; olaf@aepfle.de;
> apw@canonical.com; jasowang@redhat.com
> Subject: Re: [PATCH V5 1/1] hv_netvsc: Use the xmit_more skb flag to
> optimize signaling the host
>
> On Sun, 2015-05-10 at 21:08 -0700, K. Y. Srinivasan wrote:
> > Based on the information given to this driver (via the xmit_more skb flag),
> > we can defer signaling the host if more packets are on the way. This will
> help
> > make the host more efficient since it can potentially process a larger batch
> of
> > packets. Implement this optimization.
>
> trivia:
>
> I think that indirecting
> VMBUS_DATA_PACKET_FLAG_COMPLETTION_REQUESTED
> into a non-const temporary isn't very useful.
>
> Whenever overly long identifiers like VMBUS_<FOO> is used,
> I think that it'd be better to use it directly and ignore
> 80 column warnings.
Thanks Joe; if Dave agrees, I can send v6 of this patch out.
Regards,
K. Y
>
> Same with the "sizeof(struct nvsp_message)" on two lines.
>
> > diff --git a/drivers/net/hyperv/netvsc.c b/drivers/net/hyperv/netvsc.c
> []
> > @@ -743,6 +743,8 @@ static inline int netvsc_send_pkt(
> > u64 req_id;
> > int ret;
> > struct hv_page_buffer *pgbuf;
> > + u32 vmbus_flags =
> VMBUS_DATA_PACKET_FLAG_COMPLETION_REQUESTED;
> > + u32 ring_avail = hv_ringbuf_avail_percent(&out_channel-
> >outbound);
> []
> > @@ -769,30 +771,41 @@ static inline int netvsc_send_pkt(
> []
> > + ret = vmbus_sendpacket_pagebuffer_ctl(out_channel,
> > + pgbuf,
> > + packet->page_buf_cnt,
> > + &nvmsg,
> > + sizeof(struct
> > + nvsp_message),
> > + req_id,
> > + vmbus_flags,
> > + !packet->xmit_more);
>
> []
>
> > netif_tx_stop_queue(netdev_get_tx_queue(
> > ndev, q_idx));
>
> This could be on one line too.
>
^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: [PATCH V5 1/1] hv_netvsc: Use the xmit_more skb flag to optimize signaling the host
2015-05-11 8:59 ` KY Srinivasan
@ 2015-05-11 14:41 ` David Miller
0 siblings, 0 replies; 4+ messages in thread
From: David Miller @ 2015-05-11 14:41 UTC (permalink / raw)
To: kys; +Cc: joe, netdev, linux-kernel, devel, olaf, apw, jasowang
From: KY Srinivasan <kys@microsoft.com>
Date: Mon, 11 May 2015 08:59:53 +0000
>
>
>> -----Original Message-----
>> From: Joe Perches [mailto:joe@perches.com]
>> Sent: Sunday, May 10, 2015 10:58 PM
>> To: KY Srinivasan
>> Cc: davem@davemloft.net; netdev@vger.kernel.org; linux-
>> kernel@vger.kernel.org; devel@linuxdriverproject.org; olaf@aepfle.de;
>> apw@canonical.com; jasowang@redhat.com
>> Subject: Re: [PATCH V5 1/1] hv_netvsc: Use the xmit_more skb flag to
>> optimize signaling the host
>>
>> On Sun, 2015-05-10 at 21:08 -0700, K. Y. Srinivasan wrote:
>> > Based on the information given to this driver (via the xmit_more skb flag),
>> > we can defer signaling the host if more packets are on the way. This will
>> help
>> > make the host more efficient since it can potentially process a larger batch
>> of
>> > packets. Implement this optimization.
>>
>> trivia:
>>
>> I think that indirecting
>> VMBUS_DATA_PACKET_FLAG_COMPLETTION_REQUESTED
>> into a non-const temporary isn't very useful.
>>
>> Whenever overly long identifiers like VMBUS_<FOO> is used,
>> I think that it'd be better to use it directly and ignore
>> 80 column warnings.
>
> Thanks Joe; if Dave agrees, I can send v6 of this patch out.
Sure, respin a v6.
^ permalink raw reply [flat|nested] 4+ messages in thread
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2015-05-11 4:08 [PATCH V5 1/1] hv_netvsc: Use the xmit_more skb flag to optimize signaling the host K. Y. Srinivasan
2015-05-11 5:58 ` Joe Perches
2015-05-11 8:59 ` KY Srinivasan
2015-05-11 14:41 ` David Miller
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