Re: [PATCH v2 00/11] Improve preemptive ENOSPC flushing

[Nikolay Borisov <nborisov@suse.com>]

On 8.10.20 г. 23:48 ч., Josef Bacik wrote:
> There's a lot of individual changes, but most of it revolves around fixing the
> O_DIRECT regression that Nikolay noted.  With this set of patches we get
> slightly better performance in the buffered case than before, and the O_DIRECT
> case is slightly improved from baseline as well.
> 
> v1->v2:
> - Added a FORCE_COMMIT_TRANS flush operation so we can keep the flush_space
>   stuff consistent and get all the normal tracepoints.
> - Renamed fs_info->dio_bytes to ->ordered_bytes and changed it to count all
>   ordered extents that were pending, not just DIO ordered extents that were
>   pending.
> - Reworked the clamping to not apply if we're not doing a lot of delalloc
>   reservations.
> - Reworked the preempt flushing loop to be more straightforward.
> - Fixed the need_preemptive_flushing() helper to take into account DIO heavy
>   workloads.
> 
<snip>

So indeed it seems to result in slightly better results: 

dio-josef-v2:
  WRITE: bw=48.6MiB/s (50.0MB/s), 48.6MiB/s-48.6MiB/s (50.0MB/s-50.0MB/s), io=8192MiB (8590MB), run=168534-168534msec
  WRITE: bw=50.4MiB/s (52.8MB/s), 50.4MiB/s-50.4MiB/s (52.8MB/s-52.8MB/s), io=8192MiB (8590MB), run=162601-162601msec
  WRITE: bw=50.9MiB/s (53.4MB/s), 50.9MiB/s-50.9MiB/s (53.4MB/s-53.4MB/s), io=8192MiB (8590MB), run=160964-160964msec
  WRITE: bw=50.6MiB/s (53.0MB/s), 50.6MiB/s-50.6MiB/s (53.0MB/s-53.0MB/s), io=8192MiB (8590MB), run=161938-161938msec
  WRITE: bw=49.8MiB/s (52.2MB/s), 49.8MiB/s-49.8MiB/s (52.2MB/s-52.2MB/s), io=8192MiB (8590MB), run=164577-164577msec


buffered-josef-v2:

  WRITE: bw=32.0MiB/s (33.6MB/s), 32.0MiB/s-32.0MiB/s (33.6MB/s-33.6MB/s), io=8192MiB (8590MB), run=255670-255670msec
  WRITE: bw=29.5MiB/s (30.9MB/s), 29.5MiB/s-29.5MiB/s (30.9MB/s-30.9MB/s), io=8192MiB (8590MB), run=277829-277829msec
  WRITE: bw=31.8MiB/s (33.4MB/s), 31.8MiB/s-31.8MiB/s (33.4MB/s-33.4MB/s), io=8192MiB (8590MB), run=257554-257554msec
  WRITE: bw=29.8MiB/s (31.3MB/s), 29.8MiB/s-29.8MiB/s (31.3MB/s-31.3MB/s), io=8192MiB (8590MB), run=274516-274516msec
  WRITE: bw=29.8MiB/s (31.2MB/s), 29.8MiB/s-29.8MiB/s (31.2MB/s-31.2MB/s), io=8192MiB (8590MB), run=274975-274975msec

In comparison with V1 posting: 

buffered-josef-v1:
 WRITE: bw=29.1MiB/s (30.5MB/s), 29.1MiB/s-29.1MiB/s (30.5MB/s-30.5MB/s), io=8192MiB (8590MB), run=281678-281678msec
 WRITE: bw=30.0MiB/s (32.5MB/s), 30.0MiB/s-30.0MiB/s (32.5MB/s-32.5MB/s), io=8192MiB (8590MB), run=264337-264337msec
 WRITE: bw=29.6MiB/s (31.1MB/s), 29.6MiB/s-29.6MiB/s (31.1MB/s-31.1MB/s), io=8192MiB (8590MB), run=276312-276312msec
 WRITE: bw=29.8MiB/s (31.2MB/s), 29.8MiB/s-29.8MiB/s (31.2MB/s-31.2MB/s), io=8192MiB (8590MB), run=274916-274916msec
 WRITE: bw=30.4MiB/s (31.9MB/s), 30.4MiB/s-30.4MiB/s (31.9MB/s-31.9MB/s), io=8192MiB (8590MB), run=269030-269030msec

buffered-misc-next-no-josef:
  WRITE: bw=20.2MiB/s (21.2MB/s), 20.2MiB/s-20.2MiB/s (21.2MB/s-21.2MB/s), io=8192MiB (8590MB), run=404831-404831msec
  WRITE: bw=20.8MiB/s (21.8MB/s), 20.8MiB/s-20.8MiB/s (21.8MB/s-21.8MB/s), io=8192MiB (8590MB), run=394749-394749msec
  WRITE: bw=20.8MiB/s (21.8MB/s), 20.8MiB/s-20.8MiB/s (21.8MB/s-21.8MB/s), io=8192MiB (8590MB), run=393291-393291msec
  WRITE: bw=20.7MiB/s (21.8MB/s), 20.7MiB/s-20.7MiB/s (21.8MB/s-21.8MB/s), io=8192MiB (8590MB), run=394918-394918msec
  WRITE: bw=21.1MiB/s (22.1MB/s), 21.1MiB/s-21.1MiB/s (22.1MB/s-22.1MB/s), io=8192MiB (8590MB), run=388499-388499msec

buffered-4.19.x:
  WRITE: bw=23.3MiB/s (24.4MB/s), 23.3MiB/s-23.3MiB/s (24.4MB/s-24.4MB/s), io=6387MiB (6697MB), run=274460-274460msec
  WRITE: bw=23.3MiB/s (24.5MB/s), 23.3MiB/s-23.3MiB/s (24.5MB/s-24.5MB/s), io=6643MiB (6966MB), run=284518-284518msec
  WRITE: bw=23.4MiB/s (24.5MB/s), 23.4MiB/s-23.4MiB/s (24.5MB/s-24.5MB/s), io=6643MiB (6966MB), run=284372-284372msec
  WRITE: bw=23.6MiB/s (24.7MB/s), 23.6MiB/s-23.6MiB/s (24.7MB/s-24.7MB/s), io=6387MiB (6697MB), run=271200-271200msec
  WRITE: bw=23.4MiB/s (24.6MB/s), 23.4MiB/s-23.4MiB/s (24.6MB/s-24.6MB/s), io=6387MiB (6697MB), run=272670-272670msec

And dio: 

dio-josef-v1:
  WRITE: bw=47.1MiB/s (49.4MB/s), 47.1MiB/s-47.1MiB/s (49.4MB/s-49.4MB/s), io=8192MiB (8590MB), run=174049-174049msec
  WRITE: bw=48.5MiB/s (50.8MB/s), 48.5MiB/s-48.5MiB/s (50.8MB/s-50.8MB/s), io=8192MiB (8590MB), run=169045-169045msec
  WRITE: bw=45.0MiB/s (48.2MB/s), 45.0MiB/s-45.0MiB/s (48.2MB/s-48.2MB/s), io=8192MiB (8590MB), run=178196-178196msec
  WRITE: bw=46.1MiB/s (48.3MB/s), 46.1MiB/s-46.1MiB/s (48.3MB/s-48.3MB/s), io=8192MiB (8590MB), run=177861-177861msec
  WRITE: bw=46.4MiB/s (48.7MB/s), 46.4MiB/s-46.4MiB/s (48.7MB/s-48.7MB/s), io=8192MiB (8590MB), run=176376-176376msec

dio-misc-next-no-josef:
  WRITE: bw=50.1MiB/s (52.6MB/s), 50.1MiB/s-50.1MiB/s (52.6MB/s-52.6MB/s), io=8192MiB (8590MB), run=163365-163365msec
  WRITE: bw=50.3MiB/s (52.8MB/s), 50.3MiB/s-50.3MiB/s (52.8MB/s-52.8MB/s), io=8192MiB (8590MB), run=162753-162753msec
  WRITE: bw=50.6MiB/s (53.1MB/s), 50.6MiB/s-50.6MiB/s (53.1MB/s-53.1MB/s), io=8192MiB (8590MB), run=161766-161766msec
  WRITE: bw=50.2MiB/s (52.7MB/s), 50.2MiB/s-50.2MiB/s (52.7MB/s-52.7MB/s), io=8192MiB (8590MB), run=163074-163074msec
  WRITE: bw=50.5MiB/s (52.9MB/s), 50.5MiB/s-50.5MiB/s (52.9MB/s-52.9MB/s), io=8192MiB (8590MB), run=162252-162252msec

With this: 

Tested-by: Nikolay Borisov <nborisov@suse.com>