RE: [PATCH net-next 1/2] net: Keep sk->sk_forward_alloc as a proper size

Zhang, Cathy
2023-05-10T07:03:53Z

> -----Original Message-----
> From: Shakeel Butt <shakeelb@google.com>
> Sent: Wednesday, May 10, 2023 2:18 AM
> To: Chen, Tim C <tim.c.chen@intel.com>
> Cc: Zhang, Cathy <cathy.zhang@intel.com>; edumazet@google.com;
> davem@davemloft.net; kuba@kernel.org; pabeni@redhat.com; Brandeburg,
> Jesse <jesse.brandeburg@intel.com>; Srinivas, Suresh
> <suresh.srinivas@intel.com>; You, Lizhen <lizhen.you@intel.com>;
> eric.dumazet@gmail.com; netdev@vger.kernel.org; linux-mm@kvack.org;
> cgroups@vger.kernel.org
> Subject: Re: [PATCH net-next 1/2] net: Keep sk->sk_forward_alloc as a proper
> size
>
> On Tue, May 9, 2023 at 11:04 AM Chen, Tim C <tim.c.chen@intel.com> wrote:
> >
> > >>
> > >> Run memcached with memtier_benchamrk to verify the optimization
> > >> fix. 8 server-client pairs are created with bridge network on
> > >> localhost, server and client of the same pair share 28 logical CPUs.
> > >>
> > > >Results (Average for 5 run)
> > > >RPS (with/without patch) +2.07x
> > > >
> >
> > >Do you have regression data from any production workload? Please keep
> in mind that many times we (MM subsystem) accepts the regressions of
> microbenchmarks over complicated optimizations. So, if there is a real
> production regression, please be very explicit about it.
> >
> > Though memcached is actually used by people in production. So this isn't
> an unrealistic scenario.
> >
>
> Yes, memcached is used in production but I am not sure anyone runs 8 pairs
> of server and client on the same machine for production workload. Anyways,
> we can discuss, if needed, about the practicality of the benchmark after we
> have some impactful memcg optimizations.

The test is run on platform with 224 CPUs (HT enabled). It's not a must to run
8 pairs, the memcg charge hot paths can be observed if we run only one pair
but with more CPUs. Leverage all CPU resources on TCP connection to stress
contentions.

>
> > Tim