1:04 a.m.
On Thu, Feb 04, 2021 at 01:19:47PM +0800, Xing Zhengjun wrote:
On 2/3/2021 10:49 AM, Roman Gushchin wrote:
> On Tue, Feb 02, 2021 at 04:18:27PM +0800, Xing, Zhengjun wrote:
> > On 1/14/2021 11:18 AM, Roman Gushchin wrote:
> > > On Thu, Jan 14, 2021 at 10:51:51AM +0800, kernel test robot wrote:
> > > > Greeting,
> > > >
> > > > FYI, we noticed a -62.4% regression of hackbench.throughput due to
commit:
> > > Hi!
> > >
> > > Commit "mm: memcg/slab: optimize objcg stock draining"
(currently only in the mm tree,
> > > so no stable hash) should improve the hackbench regression.
> > The commit has been merged into Linux mainline :
> > 3de7d4f25a7438f09fef4e71ef111f1805cd8e7c ("mm: memcg/slab: optimize
objcg
> > stock draining")
> > I test the regression still existed.
> Hm, so in your setup it's about the same with and without this commit?
>
> It's strange because I've received a letter stating a 45.2% improvement
recently:
> https://lkml.org/lkml/2021/1/27/83
They are different test cases, 45.2% improvement test case run in "thread"
mode, -62.4% regression test case run in "process" mode.
Thank you for the clarification!
From 286e04b8ed7a0427 to 3de7d4f25a7438f09fef4e71ef1 there are two
regressions for process mode :
1) 286e04b8ed7a0427 to 10befea91b61c4e2c2d1df06a2e (-62.4% regression)
2) 10befea91b61c4e2c2d1df06a2e to d3921cb8be29ce5668c64e23ffd (-22.3% regression)
3de7d4f25a7438f09fef4e71ef111f1805cd8e7c only fix the regression 2) , so the value of
"hackbench.throughput" for 3de7d4f25a7438f09fef4e71ef1(71824) and
10befea91b61c4e2c2d1df06a2e (72220) is very closed.
Ok, it seems that 1) is caused by switching to per-object accounting/stats of slab
memory.
I don't now anything about 2). There are 38326 commits in between. Do you know which
commits
are causing it?
I believe that 3de7d4f25a74 partially fixes regression 1).
I'll take a look what we can do here.
Some regression could be unavoidable: we're doing more precise accounting, but it
requires
more work. As a compensation we're getting major benefits like saving over 40% of
the slab memory and having less fragmentation.
But hopefully we can make it smaller.
Thanks!