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Mon, 27 Nov 2023 13:14:20 -0800 (PST) MIME-Version: 1.0 References: <20231116022411.2250072-4-yosryahmed@google.com> <202311221542.973f16ad-oliver.sang@intel.com> In-Reply-To: <202311221542.973f16ad-oliver.sang@intel.com> From: Yosry Ahmed Date: Mon, 27 Nov 2023 13:13:44 -0800 Message-ID: Subject: Re: [PATCH v3 3/5] mm: memcg: make stats flushing threshold per-memcg To: kernel test robot 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: wnd9e6m7qfxyggxk5zxc5ohnympd7pt5 X-Rspamd-Server: rspam07 X-Rspamd-Queue-Id: 357CC40005 X-HE-Tag: 1701119661-119980 X-HE-Meta: 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 y8m4Skf5 MEaIaqQuF4YFCGWxtnOFmeNXpq74bxBxcljYmGN1KHKdzlMLhAEhKR1QJ9d5VI/rvfXCLL6IIRX9IC5cO6khl9z5n+J3sLONb+kZf/QvXS1X5Q+sYuLjzr2/ejmN08TX9S+PZj8TIwKuE2LDOioDgkGqmGcwuEU/7UC74GYbyIcUC5tOrrmnaWpxsQIs0ns1HDHmk/eTYn4o0p73UdyTkFReKQCeHGC606UTFxM64wqS9vvojVNLeJSdq0QUeFguLHyFmbGzSCVRr2JdX7NH2M3p9zqFcbfV6Cs1maypAIDs75JIOrWjAX4SL58TDlSQvjhGiZQZBte9GRjMewlzwOEBM//ACPdusScCw 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 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_thread= _ops on: > > > commit: c7fbfc7b4e089c4a9b292b1973a42a5761c1342f ("[PATCH v3 3/5] mm: mem= cg: make stats flushing threshold per-memcg") > url: https://github.com/intel-lab-lkp/linux/commits/Yosry-Ahmed/mm-memcg-= change-flush_next_time-to-flush_last_time/20231116-103300 > base: https://git.kernel.org/cgit/linux/kernel/git/akpm/mm.git mm-everyth= ing > patch link: https://lore.kernel.org/all/20231116022411.2250072-4-yosryahm= ed@google.com/ > patch subject: [PATCH v3 3/5] mm: memcg: make stats flushing threshold pe= r-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= / 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.