Re: Request for Testing: TCP RACK

From: <tuexen_at_freebsd.org>
Date: Mon, 18 Mar 2024 12:04:40 UTC
> On 18. Mar 2024, at 12:42, Nuno Teixeira <eduardo@freebsd.org> wrote:
> 
> Hello all!
> 
> It works just fine!
> System performance is OK.
> Using patch on main-n268841-b0aaf8beb126(-dirty).
> 
> ---
> net.inet.tcp.functions_available:
> Stack                           D Alias                            PCB count
> freebsd                           freebsd                          0
> rack                            * rack                             38
> ---
> 
> It would be so nice that we can have a sysctl tunnable for this patch
> so we could do more tests without recompiling kernel.
Thanks for testing!

@gallatin: can you come up with a patch that is acceptable for Netflix
and allows to mitigate the performance regression.

Best regards
Michael
> 
> Thanks all!
> Really happy here :)
> 
> Cheers,
> 
> Nuno Teixeira <eduardo@freebsd.org> escreveu (domingo, 17/03/2024 à(s) 20:26):
>> 
>> Hello,
>> 
>>> I don't have the full context, but it seems like the complaint is a performance regression in bonnie++ and perhaps other things when tcp_hpts is loaded, even when it is not used.  Is that correct?
>>> 
>>> If so, I suspect its because we drive the tcp_hpts_softclock() routine from userret(), in order to avoid tons of timer interrupts and context switches.  To test this theory,  you could apply a patch like:
>> 
>> It's affecting overall system performance, bonnie was just a way to
>> get some numbers to compare.
>> 
>> Tomorrow I will test patch.
>> 
>> Thanks!
>> 
>> --
>> Nuno Teixeira
>> FreeBSD Committer (ports)
> 
> 
> 
> -- 
> Nuno Teixeira
> FreeBSD Committer (ports)