From: Arseniy Krasnov <avkrasnov@sberdevices.ru>
To: Stefano Garzarella <sgarzare@redhat.com>
Cc: Stefan Hajnoczi <stefanha@redhat.com>,
"David S. Miller" <davem@davemloft.net>,
Eric Dumazet <edumazet@google.com>,
Jakub Kicinski <kuba@kernel.org>, Paolo Abeni <pabeni@redhat.com>,
"Michael S. Tsirkin" <mst@redhat.com>,
Jason Wang <jasowang@redhat.com>,
Bobby Eshleman <bobby.eshleman@bytedance.com>,
<kvm@vger.kernel.org>,
<virtualization@lists.linux-foundation.org>,
<netdev@vger.kernel.org>, <linux-kernel@vger.kernel.org>,
<kernel@sberdevices.ru>, <oxffffaa@gmail.com>
Subject: Re: [RFC PATCH v5 14/17] docs: net: description of MSG_ZEROCOPY for AF_VSOCK
Date: Fri, 7 Jul 2023 07:45:40 +0300 [thread overview]
Message-ID: <7e2407b7-fcdd-f047-66be-87ab371301f0@sberdevices.ru> (raw)
In-Reply-To: <CAGxU2F410NSNSzdNS4m-9UM8rZFBFpe5LeNZtkF0VzJc5_JFmg@mail.gmail.com>
On 06.07.2023 20:06, Stefano Garzarella wrote:
> On Sat, Jul 01, 2023 at 09:39:44AM +0300, Arseniy Krasnov wrote:
>> This adds description of MSG_ZEROCOPY flag support for AF_VSOCK type of
>> socket.
>>
>> Signed-off-by: Arseniy Krasnov <AVKrasnov@sberdevices.ru>
>> ---
>> Documentation/networking/msg_zerocopy.rst | 12 ++++++++++--
>> 1 file changed, 10 insertions(+), 2 deletions(-)
>>
>> diff --git a/Documentation/networking/msg_zerocopy.rst b/Documentation/networking/msg_zerocopy.rst
>> index b3ea96af9b49..34bc7ff411ce 100644
>> --- a/Documentation/networking/msg_zerocopy.rst
>> +++ b/Documentation/networking/msg_zerocopy.rst
>> @@ -7,7 +7,8 @@ Intro
>> =====
>>
>> The MSG_ZEROCOPY flag enables copy avoidance for socket send calls.
>> -The feature is currently implemented for TCP and UDP sockets.
>> +The feature is currently implemented for TCP, UDP and VSOCK (with
>> +virtio transport) sockets.
>>
>>
>> Opportunity and Caveats
>> @@ -174,7 +175,7 @@ read_notification() call in the previous snippet. A notification
>> is encoded in the standard error format, sock_extended_err.
>>
>> The level and type fields in the control data are protocol family
>> -specific, IP_RECVERR or IPV6_RECVERR.
>> +specific, IP_RECVERR or IPV6_RECVERR (for TCP or UDP socket).
>>
>> Error origin is the new type SO_EE_ORIGIN_ZEROCOPY. ee_errno is zero,
>> as explained before, to avoid blocking read and write system calls on
>> @@ -201,6 +202,7 @@ undefined, bar for ee_code, as discussed below.
>>
>> printf("completed: %u..%u\n", serr->ee_info, serr->ee_data);
>>
>> +For VSOCK socket, cmsg_level will be SOL_VSOCK and cmsg_type will be 0.
>
> Maybe better to move up, just under the previous change.
>
> By the way, should we define a valid type value for vsock
> (e.g. VSOCK_RECVERR)?
Yes I think, I'll add it in the same patch which adds SOL_VSOCK.
Thanks, Arseniy
>
>>
>> Deferred copies
>> ~~~~~~~~~~~~~~~
>> @@ -235,12 +237,15 @@ Implementation
>> Loopback
>> --------
>>
>> +For TCP and UDP:
>> Data sent to local sockets can be queued indefinitely if the receive
>> process does not read its socket. Unbound notification latency is not
>> acceptable. For this reason all packets generated with MSG_ZEROCOPY
>> that are looped to a local socket will incur a deferred copy. This
>> includes looping onto packet sockets (e.g., tcpdump) and tun devices.
>>
>> +For VSOCK:
>> +Data path sent to local sockets is the same as for non-local sockets.
>>
>> Testing
>> =======
>> @@ -254,3 +259,6 @@ instance when run with msg_zerocopy.sh between a veth pair across
>> namespaces, the test will not show any improvement. For testing, the
>> loopback restriction can be temporarily relaxed by making
>> skb_orphan_frags_rx identical to skb_orphan_frags.
>> +
>> +For VSOCK type of socket example can be found in tools/testing/vsock/
>> +vsock_test_zerocopy.c.
>
> For VSOCK socket, example can be found in
> tools/testing/vsock/vsock_test_zerocopy.c
>
> (we should leave the entire path on the same line)
>
>> --
>> 2.25.1
>>
>
next prev parent reply other threads:[~2023-07-07 4:50 UTC|newest]
Thread overview: 40+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-07-01 6:39 [RFC PATCH v5 00/17] vsock: MSG_ZEROCOPY flag support Arseniy Krasnov
2023-07-01 6:39 ` [RFC PATCH v5 01/17] vsock/virtio: read data from non-linear skb Arseniy Krasnov
2023-07-06 16:47 ` Stefano Garzarella
2023-07-01 6:39 ` [RFC PATCH v5 02/17] vhost/vsock: " Arseniy Krasnov
2023-07-06 16:49 ` Stefano Garzarella
2023-07-01 6:39 ` [RFC PATCH v5 03/17] vsock/virtio: support to send " Arseniy Krasnov
2023-07-06 16:51 ` Stefano Garzarella
2023-07-01 6:39 ` [RFC PATCH v5 04/17] vsock/virtio: non-linear skb handling for tap Arseniy Krasnov
2023-07-06 16:51 ` Stefano Garzarella
2023-07-01 6:39 ` [RFC PATCH v5 05/17] vsock/virtio: MSG_ZEROCOPY flag support Arseniy Krasnov
2023-07-06 16:53 ` Stefano Garzarella
2023-07-01 6:39 ` [RFC PATCH v5 06/17] vsock: fix EPOLLERR set on non-empty error queue Arseniy Krasnov
2023-07-06 16:54 ` Stefano Garzarella
2023-07-01 6:39 ` [RFC PATCH v5 07/17] vsock: read from socket's " Arseniy Krasnov
2023-07-06 16:54 ` Stefano Garzarella
2023-07-01 6:39 ` [RFC PATCH v5 08/17] vsock: check for MSG_ZEROCOPY support on send Arseniy Krasnov
2023-07-06 16:55 ` Stefano Garzarella
2023-07-01 6:39 ` [RFC PATCH v5 09/17] vsock: enable SOCK_SUPPORT_ZC bit Arseniy Krasnov
2023-07-06 16:55 ` Stefano Garzarella
2023-07-01 6:39 ` [RFC PATCH v5 10/17] vhost/vsock: support MSG_ZEROCOPY for transport Arseniy Krasnov
2023-07-06 16:55 ` Stefano Garzarella
2023-07-01 6:39 ` [RFC PATCH v5 11/17] vsock/virtio: " Arseniy Krasnov
2023-07-06 16:55 ` Stefano Garzarella
2023-07-01 6:39 ` [RFC PATCH v5 12/17] vsock/loopback: " Arseniy Krasnov
2023-07-06 16:56 ` Stefano Garzarella
2023-07-01 6:39 ` [RFC PATCH v5 13/17] vsock: enable setting SO_ZEROCOPY Arseniy Krasnov
2023-07-06 16:56 ` Stefano Garzarella
2023-07-12 22:31 ` Bobby Eshleman
2023-07-13 4:37 ` Arseniy Krasnov
2023-07-01 6:39 ` [RFC PATCH v5 14/17] docs: net: description of MSG_ZEROCOPY for AF_VSOCK Arseniy Krasnov
2023-07-06 17:06 ` Stefano Garzarella
2023-07-07 4:45 ` Arseniy Krasnov [this message]
2023-07-01 6:39 ` [RFC PATCH v5 15/17] test/vsock: MSG_ZEROCOPY flag tests Arseniy Krasnov
2023-07-01 6:39 ` [RFC PATCH v5 16/17] test/vsock: MSG_ZEROCOPY support for vsock_perf Arseniy Krasnov
2023-07-01 6:39 ` [RFC PATCH v5 17/17] test/vsock: io_uring rx/tx tests Arseniy Krasnov
2023-07-06 17:06 ` Stefano Garzarella
2023-07-07 4:47 ` Arseniy Krasnov
2023-07-06 17:07 ` [RFC PATCH v5 00/17] vsock: MSG_ZEROCOPY flag support Stefano Garzarella
2023-07-07 4:41 ` Arseniy Krasnov
-- strict thread matches above, loose matches on Subject: below --
2023-07-01 6:22 Arseniy Krasnov
2023-07-01 6:23 ` [RFC PATCH v5 14/17] docs: net: description of MSG_ZEROCOPY for AF_VSOCK Arseniy Krasnov
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