On Tue, 7 Mar 2023 14:55:57 +0800 Qi Zheng <zhengqi.arch@xxxxxxxxxxxxx> 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?
