Re: [PATCH -mm -V3 00/21] mm, THP, swap: Swapout/swapin THP in one piece

From: Daniel Jordan
Date: Mon Jun 04 2018 - 14:06:57 EST


On Wed, May 23, 2018 at 04:26:04PM +0800, Huang, Ying wrote:
> And for all, Any comment is welcome!
>
> This patchset is based on the 2018-05-18 head of mmotm/master.

Trying to review this and it doesn't apply to mmotm-2018-05-18-16-44. git
fails on patch 10:

Applying: mm, THP, swap: Support to count THP swapin and its fallback
error: Documentation/vm/transhuge.rst: does not exist in index
Patch failed at 0010 mm, THP, swap: Support to count THP swapin and its fallback

Sure enough, this tag has Documentation/vm/transhuge.txt but not the .rst
version. Was this the tag you meant? If so did you pull in some of Mike
Rapoport's doc changes on top?

> base optimized
> ---------------- --------------------------
> %stddev %change %stddev
> \ | \
> 1417897 ± 2% +992.8% 15494673 vm-scalability.throughput
> 1020489 ± 4% +1091.2% 12156349 vmstat.swap.si
> 1255093 ± 3% +940.3% 13056114 vmstat.swap.so
> 1259769 ± 7% +1818.3% 24166779 meminfo.AnonHugePages
> 28021761 -10.7% 25018848 ± 2% meminfo.AnonPages
> 64080064 ± 4% -95.6% 2787565 ± 33% interrupts.CAL:Function_call_interrupts
> 13.91 ± 5% -13.8 0.10 ± 27% perf-profile.children.cycles-pp.native_queued_spin_lock_slowpath
>
...snip...
> test, while in optimized kernel, that is 96.6%. The TLB flushing IPI
> (represented as interrupts.CAL:Function_call_interrupts) reduced
> 95.6%, while cycles for spinlock reduced from 13.9% to 0.1%. These
> are performance benefit of THP swapout/swapin too.

Which spinlocks are we spending less time on?