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author | Jens Axboe <axboe@fb.com> | 2016-11-09 12:36:15 -0700 |
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committer | Jens Axboe <axboe@fb.com> | 2016-11-10 13:53:32 -0700 |
commit | e34cbd307477ae07c5d8a8d0bd15e65a9ddaba5c (patch) | |
tree | 2cf40c43afdc01d953eae0098c4f8bb4d760c8d9 /Documentation | |
parent | cf43e6be865a582ba66ee4747ae27a0513f6bba1 (diff) |
blk-wbt: add general throttling mechanism
We can hook this up to the block layer, to help throttle buffered
writes.
wbt registers a few trace points that can be used to track what is
happening in the system:
wbt_lat: 259:0: latency 2446318
wbt_stat: 259:0: rmean=2446318, rmin=2446318, rmax=2446318, rsamples=1,
wmean=518866, wmin=15522, wmax=5330353, wsamples=57
wbt_step: 259:0: step down: step=1, window=72727272, background=8, normal=16, max=32
This shows a sync issue event (wbt_lat) that exceeded it's time. wbt_stat
dumps the current read/write stats for that window, and wbt_step shows a
step down event where we now scale back writes. Each trace includes the
device, 259:0 in this case.
Signed-off-by: Jens Axboe <axboe@fb.com>
Diffstat (limited to 'Documentation')
0 files changed, 0 insertions, 0 deletions