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Mon, 27 Nov 2023 17:59:00 -0800 (PST) MIME-Version: 1.0 References: <20231116022411.2250072-4-yosryahmed@google.com> <202311221542.973f16ad-oliver.sang@intel.com> In-Reply-To: From: Yosry Ahmed Date: Mon, 27 Nov 2023 17:58:24 -0800 Message-ID: Subject: Re: [PATCH v3 3/5] mm: memcg: make stats flushing threshold per-memcg To: Oliver Sang Cc: oe-lkp@lists.linux.dev, lkp@intel.com, Johannes Weiner , Domenico Cerasuolo , cgroups@vger.kernel.org, linux-mm@kvack.org, ying.huang@intel.com, feng.tang@intel.com, fengwei.yin@intel.com, Andrew Morton , Michal Hocko , Roman Gushchin , Shakeel Butt , Muchun Song , Ivan Babrou , Tejun Heo , =?UTF-8?Q?Michal_Koutn=C3=BD?= , Waiman Long , kernel-team@cloudflare.com, Wei Xu , Greg Thelen , linux-kernel@vger.kernel.org Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable X-Rspam-User: X-Stat-Signature: 61qo6p5koyhkbtpdr6rtqfq3uj83ejfa X-Rspamd-Server: rspam07 X-Rspamd-Queue-Id: 42F3540847 X-HE-Tag: 1701136741-966998 X-HE-Meta: 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 F9kJ+4sO QXApXl/JZTXQHjQh6NtZIpuV1IjuFTewlTFa4oIu0dMHQQSlarG2iP34+B16KeTuEM9s8egibl3bPP4jnSSLEYF+zG1nlBmy1UZ1MKusj3XKbeChswYMxwMERXyeCgzeWtZrt3X+PzVCXhapf7904HAGLKr+jTB7a+AUJNrmD+cVGsra8o0DVnnUeVKYmRqBrImVyFdws7WzRqccoez4R4pos4W1xK/UHZUK57gU3NEoieU6IO5h8RzE4b5Mjbr8Pag1/GdLGtZT/E1q1CGIuCzpiC26TtTszQ+9wdDNPyDRlqtkUI2buHb0KLncBB/li0qdjpIkIofnSQoRt9qGusECDd/nX3nrz9lJa X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On Mon, Nov 27, 2023 at 5:46=E2=80=AFPM Oliver Sang = wrote: > > hi, Yosry Ahmed, > > On Mon, Nov 27, 2023 at 01:13:44PM -0800, Yosry Ahmed wrote: > > On Wed, Nov 22, 2023 at 5:54=E2=80=AFAM kernel test robot wrote: > > > > > > > > > > > > Hello, > > > > > > kernel test robot noticed a -30.2% regression of will-it-scale.per_th= read_ops on: > > > > > > > > > commit: c7fbfc7b4e089c4a9b292b1973a42a5761c1342f ("[PATCH v3 3/5] mm:= memcg: make stats flushing threshold per-memcg") > > > url: https://github.com/intel-lab-lkp/linux/commits/Yosry-Ahmed/mm-me= mcg-change-flush_next_time-to-flush_last_time/20231116-103300 > > > base: https://git.kernel.org/cgit/linux/kernel/git/akpm/mm.git mm-eve= rything > > > patch link: https://lore.kernel.org/all/20231116022411.2250072-4-yosr= yahmed@google.com/ > > > patch subject: [PATCH v3 3/5] mm: memcg: make stats flushing threshol= d per-memcg > > > > > > testcase: will-it-scale > > > test machine: 104 threads 2 sockets (Skylake) with 192G memory > > > parameters: > > > > > > nr_task: 50% > > > mode: thread > > > test: fallocate2 > > > cpufreq_governor: performance > > > > > > > > > > This regression was also reported in v2, and I explicitly mention it > > in the cover letter here: > > https://lore.kernel.org/lkml/20231116022411.2250072-1-yosryahmed@google= .com/ > > got it. this also reminds us to read cover letter for a patch set in the > future. Thanks! > > > > > In a nutshell, I think this microbenchmark regression does not > > represent real workloads. On the other hand, there are demonstrated > > benefits on real workloads from this series in terms of stats reading > > time. > > > > ok, if there are future versions of this patch, or when it is merged, we = will > ignore similar results. > > just a small question, since we focus on microbenchmark, if we found othe= r > regression (or improvement) on tests other than will-it-scale::fallocate, > do you want us to send report or just ignore them, either? I think it would be useful to know if there are regressions/improvements in other microbenchmarks, at least to investigate whether they represent real regressions.