linux-kernel - Re: [RFC v2 00/24] Per queue configs and large rx buffer support for zcrx

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [day] [month] [year] [list]

Message-ID: <ac041a47-98b1-4fac-86d7-487421b939e9@gmail.com>
Date: Fri, 15 Aug 2025 21:15:24 +0100
From: Pavel Begunkov <asml.silence@...il.com>
To: Dragos Tatulea <dtatulea@...dia.com>, Jakub Kicinski <kuba@...nel.org>,
 netdev@...r.kernel.org
Cc: Eric Dumazet <edumazet@...gle.com>, Willem de Bruijn
 <willemb@...gle.com>, Paolo Abeni <pabeni@...hat.com>,
 andrew+netdev@...n.ch, horms@...nel.org, davem@...emloft.net,
 sdf@...ichev.me, almasrymina@...gle.com, dw@...idwei.uk,
 michael.chan@...adcom.com, ap420073@...il.com, linux-kernel@...r.kernel.org
Subject: Re: [RFC v2 00/24] Per queue configs and large rx buffer support for
 zcrx

On 8/15/25 17:44, Dragos Tatulea wrote:
> On Thu, Aug 14, 2025 at 11:46:35AM +0100, Pavel Begunkov wrote:
...>> "-A1" here is for using huge pages, so don't forget to configure
>> /proc/sys/vm/nr_hugepages.
>>
>> # client
>> examples/send-zerocopy -6 tcp -D <ip addr> -p <port>
>>                         -t <runtime secs>
>>                         -l -b1 -n1 -z1 -d -s<send size>
>>
> Thanks a lot for the branch and the instructions Pavel! I am playing
> with them now and seeing some preliminary good results. Will post
> them once we share the patches.

Sounds good

>> I had to play with the client a bit for it to keep up with
>> the server. "-l" enables huge pages, and had to bump up the
>> send size. You can also add -v to both for a basic payload
>> verification.
>>
> I see what you mean. I also had to make the rx memory larger once

Forgot to mention that the tool doesn't consider CPU affinities,
so I had to configure task and irq affinities by hand.

> rx-buf-len >= 32K. Otherwise the traffic was hanging after a second or
> so. This is probably related to the currently known issue where if a
> page_pool is too small due to incorrect sizing of the buffer, mlx5 hangs
> on first refill. That still needs fixing.

-- 
Pavel Begunkov