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From: Laurent Vivier <lvivier@redhat.com>
To: Stefano Brivio <sbrivio@redhat.com>
Cc: David Gibson <david@gibson.dropbear.id.au>, passt-dev@passt.top
Subject: Re: [PATCH v8 7/8] vhost-user: add vhost-user
Date: Thu, 17 Oct 2024 19:25:11 +0200	[thread overview]
Message-ID: <3de3422c-3ed5-4ea7-bfc9-ceea6067bc37@redhat.com> (raw)
In-Reply-To: <100e2890-ff11-4e6f-9967-d05cc3b545d2@redhat.com>

On 17/10/2024 19:18, Laurent Vivier wrote:
> On 17/10/2024 13:25, Stefano Brivio wrote:
>> On Thu, 17 Oct 2024 02:10:31 +0200
>> Stefano Brivio <sbrivio@redhat.com> wrote:
>>
>>> On Wed, 16 Oct 2024 11:41:34 +1100
>>> David Gibson <david@gibson.dropbear.id.au> wrote:
>>>
>>>> On Tue, Oct 15, 2024 at 09:54:38PM +0200, Stefano Brivio wrote:
>>>>> [Still partial review]
>>>> [snip]
>>>>>> +    if (peek_offset_cap)
>>>>>> +        already_sent = 0;
>>>>>> +
>>>>>> +    iov_vu[0].iov_base = tcp_buf_discard;
>>>>>> +    iov_vu[0].iov_len = already_sent;
>>>>>
>>>>> I think I had a similar comment to a previous revision. Now, I haven't
>>>>> tested this (yet) on a kernel with support for SO_PEEK_OFF on TCP, but
>>>>> I think this should eventually follow the same logic as the (updated)
>>>>> tcp_buf_data_from_sock(): we should use tcp_buf_discard only if
>>>>> (!peek_offset_cap).
>>>>>
>>>>> It's fine to always initialise VIRTQUEUE_MAX_SIZE iov_vu items,
>>>>> starting from 1, for simplicity. But I'm not sure if it's safe to pass a
>>>>> zero iov_len if (peek_offset_cap).
>>>>> I'll test that (unless you already did) -- if it works, we can fix this
>>>>> up later as well.
>>>>
>>>> I believe I tested it at some point, and I think we're already using
>>>> it somewhere.
>>>
>>> I tested it again just to be sure on a recent net.git kernel: sometimes
>>> the first test in passt_vu_in_ns/tcp, "TCP/IPv4: host to guest: big
>>> transfer" hangs on my setup, sometimes it's the "TCP/IPv4: ns to guest
>>> (using loopback address): big transfer" test instead.
>>>
>>> I can reproduce at least one of the two issues consistently (tests
>>> stopped 5 times out of 5).
>>>
>>> The socat client completes the transfer, the server is still waiting
>>> for something. I haven't taken captures yet or tried to re-send from
>>> the client.
>>
>> ...Laurent, let me know if I should dig into this any further.
>>
>> For reference, the kernel commit introducing SO_PEEK_OFF support for TCP
>> on IPv6 is be9a4fb831b8 ("tcp: add SO_PEEK_OFF socket option tor
>> TCPv6"). Without that commit, passt won't set peek_offset_cap.
>>
>> It was added in 6.11-rc5, so it's part of kernel-6.11.3-200.fc40 (latest
>> stable kernel) for Fedora 40. passt will print "SO_PEEK_OFF supported"
>> if you run it with -d -f.
>>
> 
> I have kernel 6.11.3-200.fc40.x86_64 but the message is "SO_PEEK_OFF not supported".

strace gives me:

socket(AF_INET, SOCK_STREAM|SOCK_CLOEXEC, IPPROTO_TCP) = 73
setsockopt(73, SOL_SOCKET, SO_PEEK_OFF, [0], 4) = 0
socket(AF_INET6, SOCK_STREAM|SOCK_CLOEXEC, IPPROTO_TCP) = 73
setsockopt(73, SOL_SOCKET, SO_PEEK_OFF, [0], 4) = -1 EOPNOTSUPP (Operation not supported)

Thanks,
Laurent


  reply	other threads:[~2024-10-17 17:25 UTC|newest]

Thread overview: 50+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2024-10-10 12:28 [PATCH v8 0/8] Add vhost-user support to passt. (part 3) Laurent Vivier
2024-10-10 12:28 ` [PATCH v8 1/8] packet: replace struct desc by struct iovec Laurent Vivier
2024-10-10 12:28 ` [PATCH v8 2/8] vhost-user: introduce virtio API Laurent Vivier
2024-10-10 12:28 ` [PATCH v8 3/8] vhost-user: introduce vhost-user API Laurent Vivier
2024-10-10 12:28 ` [PATCH v8 4/8] udp: Prepare udp.c to be shared with vhost-user Laurent Vivier
2024-10-14  4:29   ` David Gibson
2024-10-10 12:28 ` [PATCH v8 5/8] tcp: Export headers functions Laurent Vivier
2024-10-14  4:29   ` David Gibson
2024-10-10 12:29 ` [PATCH v8 6/8] passt: rename tap_sock_init() to tap_backend_init() Laurent Vivier
2024-10-14  4:30   ` David Gibson
2024-10-14 22:38   ` Stefano Brivio
2024-10-10 12:29 ` [PATCH v8 7/8] vhost-user: add vhost-user Laurent Vivier
2024-10-15  3:23   ` David Gibson
2024-10-16 10:07     ` Laurent Vivier
2024-10-16 16:26       ` Stefano Brivio
2024-10-15 19:54   ` Stefano Brivio
2024-10-16  0:41     ` David Gibson
2024-10-17  0:10       ` Stefano Brivio
2024-10-17 11:25         ` Stefano Brivio
2024-10-17 11:54           ` Laurent Vivier
2024-10-17 17:18           ` Laurent Vivier
2024-10-17 17:25             ` Laurent Vivier [this message]
2024-10-17 17:33             ` Stefano Brivio
2024-10-17 21:21               ` Stefano Brivio
2024-10-22 12:59         ` Laurent Vivier
2024-10-22 13:19           ` Stefano Brivio
2024-10-22 18:19             ` Stefano Brivio
2024-10-22 18:22               ` Stefano Brivio
2024-10-23 15:27           ` Laurent Vivier
2024-10-23 16:23             ` Stefano Brivio
2024-10-17  0:10   ` Stefano Brivio
2024-10-17  7:28     ` Laurent Vivier
2024-10-17  8:33       ` Stefano Brivio
2024-11-14 10:20     ` Laurent Vivier
2024-11-14 14:23       ` Stefano Brivio
2024-11-14 15:16         ` Laurent Vivier
2024-11-14 15:38           ` Stefano Brivio
2024-11-14 10:23     ` Laurent Vivier
2024-11-14 14:23       ` Stefano Brivio
2024-11-15  8:30         ` Laurent Vivier
2024-11-15 10:08           ` Stefano Brivio
2024-11-14 10:29     ` Laurent Vivier
2024-11-14 14:23       ` Stefano Brivio
2024-11-15 11:13         ` Laurent Vivier
2024-11-15 11:23           ` Stefano Brivio
2024-10-10 12:29 ` [PATCH v8 8/8] test: Add tests for passt in vhost-user mode Laurent Vivier
2024-10-15  3:40   ` David Gibson
2024-10-15 19:54   ` Stefano Brivio
2024-10-16  8:06     ` Laurent Vivier
2024-10-16  9:47       ` Stefano Brivio

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