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

Oliver Sang
2022-08-16T08:31:25Z

Hi all,

now we noticed this commit has already merged into mainline, and in our tests
there is still similar regression. [1]

not sure if there is a plan to merge some of the solutions that have been
discussed in this thread? we'll very glad to test patches if there is a request

Thanks a lot!

[1]
=========================================================================================
tbox_group/testcase/rootfs/kconfig/compiler/ip/runtime/nr_threads/cluster/send_size/test/cpufreq_governor/ucode:
lkp-icl-2sp4/netperf/debian-11.1-x86_64-20220510.cgz/x86_64-rhel-8.3/gcc-11/ipv4/300s/50%/cs-localhost/10K/SCTP_STREAM_MANY/performance/0xd000363

7c80b038d23e1f4c 4890b686f4088c90432149bd6de
---------------- ---------------------------
%stddev %change %stddev
\ | \
9078 -55.9% 4006 netperf.Throughput_Mbps
581006 -55.9% 256385 netperf.Throughput_total_Mbps
36715 -54.6% 16674 ± 4% netperf.time.involuntary_context_switches
1885 -50.2% 938.33 ± 3% netperf.time.percent_of_cpu_this_job_got
5533 -49.9% 2771 ± 2% netperf.time.system_time
152.13 -59.5% 61.61 ± 2% netperf.time.user_time
418171 ± 5% +89.4% 791954 ± 17% netperf.time.voluntary_context_switches
2.128e+09 -55.9% 9.389e+08 netperf.workload
30217 +17.8% 35608 uptime.idle
2.689e+10 +20.3% 3.234e+10 cpuidle..time
6.366e+08 -48.1% 3.305e+08 cpuidle..usage
70.26 +13.5 83.78 mpstat.cpu.all.idle%
4.46 -1.5 2.92 ± 3% mpstat.cpu.all.soft%
23.71 -11.6 12.16 ± 3% mpstat.cpu.all.sys%
0.89 -0.5 0.38 mpstat.cpu.all.usr%
1.392e+09 -57.5% 5.91e+08 ± 12% numa-numastat.node0.local_node
1.389e+09 -57.5% 5.906e+08 ± 12% numa-numastat.node0.numa_hit
1.369e+09 -54.5% 6.226e+08 ± 12% numa-numastat.node1.local_node
1.366e+09 -54.4% 6.222e+08 ± 12% numa-numastat.node1.numa_hit
36715 -54.6% 16674 ± 4% time.involuntary_context_switches
1885 -50.2% 938.33 ± 3% time.percent_of_cpu_this_job_got
5533 -49.9% 2771 ± 2% time.system_time
152.13 -59.5% 61.61 ± 2% time.user_time
418171 ± 5% +89.4% 791954 ± 17% time.voluntary_context_switches

On Tue, Jul 05, 2022 at 01:03:26PM +0800, Feng Tang wrote:
> On Sun, Jul 03, 2022 at 03:55:31PM -0700, Roman Gushchin wrote:
> > 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?
>
> I think it makes sense, or also make it a configurable parameter? From
> the test reports of 0Day, these charging/counting play critical role
> in performance (easy to see up to 60% performance effect). If user only
> wants memcg for isolating things or doesn't care charging/stats, these
> seem to be extra taxes.
>
> For bumping to 64 or 128, universal improvement is expected with the
> only concern of accuracy.
>
> Thanks,
> Feng
>
> > Thanks!