lkml.org 
[lkml]   [2020]   [Aug]   [12]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectRe: [f2fs-dev] [PATCH v3] f2fs: change virtual mapping way for compression pages
On Wed, Aug 12, 2020 at 02:17:11PM +0900, Daeho Jeong wrote:
> From: Daeho Jeong <daehojeong@google.com>
>
> By profiling f2fs compression works, I've found vmap() callings have
> unexpected hikes in the execution time in our test environment and
> those are bottlenecks of f2fs decompression path. Changing these with
> vm_map_ram(), we can enhance f2fs decompression speed pretty much.
>
> [Verification]
> Android Pixel 3(ARM64, 6GB RAM, 128GB UFS)
> Turned on only 0-3 little cores(at 1.785GHz)
>
> dd if=/dev/zero of=dummy bs=1m count=1000
> echo 3 > /proc/sys/vm/drop_caches
> dd if=dummy of=/dev/zero bs=512k
>
> - w/o compression -
> 1048576000 bytes (0.9 G) copied, 2.082554 s, 480 M/s
> 1048576000 bytes (0.9 G) copied, 2.081634 s, 480 M/s
> 1048576000 bytes (0.9 G) copied, 2.090861 s, 478 M/s
>
> - before patch -
> 1048576000 bytes (0.9 G) copied, 7.407527 s, 135 M/s
> 1048576000 bytes (0.9 G) copied, 7.283734 s, 137 M/s
> 1048576000 bytes (0.9 G) copied, 7.291508 s, 137 M/s
>
> - after patch -
> 1048576000 bytes (0.9 G) copied, 1.998959 s, 500 M/s
> 1048576000 bytes (0.9 G) copied, 1.987554 s, 503 M/s
> 1048576000 bytes (0.9 G) copied, 1.986380 s, 503 M/s
>

The reason why I raised up this was that I once observed vmap() vs
vm_map_ram() on arm64 kirin platform as well. it indeed had some
impact (~10%) but not as huge as this. Anyway, such description
with test environment looks ok.

Thanks,
Gao Xiang



\
 
 \ /
  Last update: 2020-08-12 11:33    [W:0.074 / U:2.632 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site