Re: [f2fs-dev] [PATCH v3] f2fs: change virtual mapping way for compression pages

[Chao Yu]

On 2020/8/12 13:17, Daeho Jeong wrote:
> From: Daeho Jeong <daehojeong@xxxxxxxxxx>
>
> 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
>
> Signed-off-by: Daeho Jeong <daehojeong@xxxxxxxxxx>

Reviewed-by: Chao Yu <yuchao0@xxxxxxxxxx>

Thanks,