diff options
| author | Shaohua Li <[email protected]> | 2011-10-31 17:07:03 -0700 |
|---|---|---|
| committer | Linus Torvalds <[email protected]> | 2011-10-31 17:30:45 -0700 |
| commit | 3da367c3e5fca71d4e778fa565d9b098d5518f4a (patch) | |
| tree | 915dff1989bdffaed157b56f724631b5d8f2d328 /tools/perf/scripts/python/Perf-Trace-Util/lib/Perf/Trace | |
| parent | 3fa36acbced23c563345de3179dfe1775f15be5e (diff) | |
vmscan: add block plug for page reclaim
per-task block plug can reduce block queue lock contention and increase
request merge. Currently page reclaim doesn't support it. I originally
thought page reclaim doesn't need it, because kswapd thread count is
limited and file cache write is done at flusher mostly.
When I test a workload with heavy swap in a 4-node machine, each CPU is
doing direct page reclaim and swap. This causes block queue lock
contention. In my test, without below patch, the CPU utilization is about
2% ~ 7%. With the patch, the CPU utilization is about 1% ~ 3%. Disk
throughput isn't changed. This should improve normal kswapd write and
file cache write too (increase request merge for example), but might not
be so obvious as I explain above.
Signed-off-by: Shaohua Li <[email protected]>
Cc: Jens Axboe <[email protected]>
Cc: Minchan Kim <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>
Diffstat (limited to 'tools/perf/scripts/python/Perf-Trace-Util/lib/Perf/Trace')
0 files changed, 0 insertions, 0 deletions