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bh=8igepYudrBDgBGP0BH8iVimdwg7sin/v8nkfuII5Cig=; h=Date:From:To:Cc:Subject:In-Reply-To:References:From; b=A0AQYV7bOaqS9eqOoYjVsErfIDPISR8Tmf4ZT3znJM4eZsaCOrS0t2QnJLDXDjcbX bJ1c7a53HycjGRHRC+QDHPOGEXwMPfw7CgOZzha/MtZI19QVM3qtIiMaKUzue/Jyge krnCiryUXbggF/hOnuIEY7nkFvBpbSSpGBipn8s4= Date: Tue, 7 Mar 2023 14:20:26 -0800 From: Andrew Morton To: Qi Zheng Cc: tkhai@ya.ru, hannes@cmpxchg.org, shakeelb@google.com, mhocko@kernel.org, roman.gushchin@linux.dev, muchun.song@linux.dev, david@redhat.com, shy828301@gmail.com, rppt@kernel.org, sultan@kerneltoast.com, dave@stgolabs.net, penguin-kernel@I-love.SAKURA.ne.jp, paulmck@kernel.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH v4 0/8] make slab shrink lockless Message-Id: <20230307142026.31c964475fd3c9554a4f62cb@linux-foundation.org> In-Reply-To: <20230307065605.58209-1-zhengqi.arch@bytedance.com> References: <20230307065605.58209-1-zhengqi.arch@bytedance.com> X-Mailer: Sylpheed 3.8.0beta1 (GTK+ 2.24.33; x86_64-pc-linux-gnu) Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit X-Rspam-User: X-Rspamd-Server: rspam02 X-Rspamd-Queue-Id: C546E10000C X-Stat-Signature: qbt6g3kxyygnp6dmmq6yncikszsy8t8w X-HE-Tag: 1678227629-687286 X-HE-Meta: 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 42AGVGBX yLeyJ1jabxtqYkuu9yAxqxAYEuJjA7djFKjacwqFAmVjKiGEFPpeQrE0L7oZLndI5J0sRwbswKEQcIWfIIcXLMUXbgAC0PhRZxiVR/btkvr1jadaMMR0IqzgJSa7sEok892+uFLOVq2i+admFE7XHB7/ViFtbxP/UQWvQMk1C0K6qShxhMHduuK7pPPDRuKiGC+vMTDTrbwy/8RudZ10GPZooYSNUZ0K9EQ6lnzes52UdTnPB1q/98yntr1ngOC7Jf5wH+R1hYCEPVbc8BbiIGLpuCoM2ABzdlEI8sev8Eepj/o1RwkGQk5re3h0XR1tJEgcscJvHtpTASlkb8K/tB1zc/fAmAE/dF0UxKT50NrhkswwY2fGdKw4DOc10H7VYLINL5f9jHkmBRxbt9xGbWkwB5w== 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: On Tue, 7 Mar 2023 14:55:57 +0800 Qi Zheng wrote: > Hi all, > > This patch series aims to make slab shrink lockless. The v3 discussion did contain requests for some sort of measurements of real-world workloads. And Kirill did suggest a workload which could be used for this measurement. It's quite important that we have this info, please. I mean, speeding up real-world workloads is the entire point of the patchset and without measurements, we don't know if the patchset achieves its primary objective! > 3. Reproduction and testing > =========================== > > We can reproduce the down_read_trylock() hotspot through the following script: > > ``` > #!/bin/bash > > DIR="/root/shrinker/memcg/mnt" > > do_create() > { > mkdir -p /sys/fs/cgroup/memory/test > mkdir -p /sys/fs/cgroup/perf_event/test > echo 4G > /sys/fs/cgroup/memory/test/memory.limit_in_bytes > for i in `seq 0 $1`; > do > mkdir -p /sys/fs/cgroup/memory/test/$i; > echo $$ > /sys/fs/cgroup/memory/test/$i/cgroup.procs; > echo $$ > /sys/fs/cgroup/perf_event/test/cgroup.procs; > mkdir -p $DIR/$i; > done > } > > do_mount() > { > for i in `seq $1 $2`; > do > mount -t tmpfs $i $DIR/$i; > done > } > > do_touch() > { > for i in `seq $1 $2`; > do > echo $$ > /sys/fs/cgroup/memory/test/$i/cgroup.procs; > echo $$ > /sys/fs/cgroup/perf_event/test/cgroup.procs; > dd if=/dev/zero of=$DIR/$i/file$i bs=1M count=1 & > done > } > > case "$1" in > touch) > do_touch $2 $3 > ;; > test) > do_create 4000 > do_mount 0 4000 > do_touch 0 3000 > ;; > *) > exit 1 > ;; > esac > ``` > > Save the above script, then run test and touch commands. Then we can use the > following perf command to view hotspots: Well. Simply runnimg time that-script before and after and including the info in the changelog would be a start?