Re: [net] 4890b686f4: netperf.Throughput_Mbps -69.4% regression

Roman Gushchin
2022-07-03T22:55:43Z

On Sun, Jul 03, 2022 at 06:43:53PM +0800, Feng Tang wrote:
> Hi Shakeel,
>
> On Fri, Jul 01, 2022 at 08:47:29AM -0700, Shakeel Butt wrote:
> > On Mon, Jun 27, 2022 at 8:49 PM Feng Tang <feng.tang@intel.com> wrote:
> > > I just tested it, it does perform better (the 4th is with your patch),
> > > some perf-profile data is also listed.
> > >
> > > 7c80b038d23e1f4c 4890b686f4088c90432149bd6de 332b589c49656a45881bca4ecc0 e719635902654380b23ffce908d
> > > ---------------- --------------------------- --------------------------- ---------------------------
> > > 15722 -69.5% 4792 -40.8% 9300 -27.9% 11341 netperf.Throughput_Mbps
> > >
> > > 0.00 +0.3 0.26 ± 5% +0.5 0.51 +1.3 1.27 ± 2%pp.self.__sk_mem_raise_allocated
> > > 0.00 +0.3 0.32 ± 15% +1.7 1.74 ± 2% +0.4 0.40 ± 2% pp.self.propagate_protected_usage
> > > 0.00 +0.8 0.82 ± 7% +0.9 0.90 +0.8 0.84 pp.self.__mod_memcg_state
> > > 0.00 +1.2 1.24 ± 4% +1.0 1.01 +1.4 1.44 pp.self.try_charge_memcg
> > > 0.00 +2.1 2.06 +2.1 2.13 +2.1 2.11 pp.self.page_counter_uncharge
> > > 0.00 +2.1 2.14 ± 4% +2.7 2.71 +2.6 2.60 ± 2% pp.self.page_counter_try_charge
> > > 1.12 ± 4% +3.1 4.24 +1.1 2.22 +1.4 2.51 pp.self.native_queued_spin_lock_slowpath
> > > 0.28 ± 9% +3.8 4.06 ± 4% +0.2 0.48 +0.4 0.68 pp.self.sctp_eat_data
> > > 0.00 +8.2 8.23 +0.8 0.83 +1.3 1.26 pp.self.__sk_mem_reduce_allocated
> > >
> > > And the size of 'mem_cgroup' is increased from 4224 Bytes to 4608.
> >
> > Hi Feng, can you please try two more configurations? Take Eric's patch
> > of adding ____cacheline_aligned_in_smp in page_counter and for first
> > increase MEMCG_CHARGE_BATCH to 64 and for second increase it to 128.
> > Basically batch increases combined with Eric's patch.
>
> With increasing batch to 128, the regression could be reduced to -12.4%.

If we're going to bump it, I wonder if we should scale it dynamically depending
on the size of the memory cgroup?

Thanks!