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| author | Paolo Valente <paolo.valente@linaro.org> | 2021-01-22 19:19:43 +0100 |
|---|---|---|
| committer | Jens Axboe <axboe@kernel.dk> | 2021-01-24 18:18:24 -0700 |
| commit | b5f74ecacc3139ef873e69acc3aba28083ecc416 (patch) | |
| tree | 8f370be89b909cd104670a7f19c8a805ee324ef3 /block/bfq-iosched.c | |
| parent | a33df75c6328bf40078b35f2040d8e54d574c357 (diff) | |
| download | linux-b5f74ecacc3139ef873e69acc3aba28083ecc416.tar.gz linux-b5f74ecacc3139ef873e69acc3aba28083ecc416.tar.bz2 linux-b5f74ecacc3139ef873e69acc3aba28083ecc416.zip | |
block, bfq: use half slice_idle as a threshold to check short ttime
The value of the I/O plugging (idling) timeout is used also as the
think-time threshold to decide whether a process has a short think
time. In this respect, a good value of this timeout for rotational
drives is un the order of several ms. Yet, this is often too long a
time interval to be effective as a think-time threshold. This commit
mitigates this problem (by a lot, according to tests), by halving the
threshold.
Tested-by: Jan Kara <jack@suse.cz>
Signed-off-by: Paolo Valente <paolo.valente@linaro.org>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Diffstat (limited to 'block/bfq-iosched.c')
| -rw-r--r-- | block/bfq-iosched.c | 7 |
1 files changed, 4 insertions, 3 deletions
diff --git a/block/bfq-iosched.c b/block/bfq-iosched.c index 9e4eb0fc1c16..eb2ca32d5b63 100644 --- a/block/bfq-iosched.c +++ b/block/bfq-iosched.c @@ -5238,12 +5238,13 @@ static void bfq_update_has_short_ttime(struct bfq_data *bfqd, return; /* Think time is infinite if no process is linked to - * bfqq. Otherwise check average think time to - * decide whether to mark as has_short_ttime + * bfqq. Otherwise check average think time to decide whether + * to mark as has_short_ttime. To this goal, compare average + * think time with half the I/O-plugging timeout. */ if (atomic_read(&bic->icq.ioc->active_ref) == 0 || (bfq_sample_valid(bfqq->ttime.ttime_samples) && - bfqq->ttime.ttime_mean > bfqd->bfq_slice_idle)) + bfqq->ttime.ttime_mean > bfqd->bfq_slice_idle>>1)) has_short_ttime = false; state_changed = has_short_ttime != bfq_bfqq_has_short_ttime(bfqq); |