From: Jens Axboe <axboe@kernel.dk>
To: linux-block@vger.kernel.org
Subject: [PATCHSET v2 0/6] blk-mq: per-ctx tag caching
Date: Tue, 7 Jan 2020 09:30:31 -0700 [thread overview]
Message-ID: <20200107163037.31745-1-axboe@kernel.dk> (raw)
Here's v2 of this patchset. It should be solid now, the previous version
didn't handle tag flushing correctly, or multiple hardware queue types.
The idea here is that we can reduce the cost of getting a tag for a new
request, if we don't get them piecemeal. Add a per-ctx tag cache, and
grab batches of tags if it's empty. If it's not empty, we can just find
a free bit there.
/sys/kernel/debug/block/<dev>/<hctx>/<cpu>/tag_hit holds some stats
associated with this, so you can check how it's doing.
I've seen nice improvements with this in testing.
--
Jens Axboe
next reply other threads:[~2020-01-07 16:30 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-01-07 16:30 Jens Axboe [this message]
2020-01-07 16:30 ` [PATCH 1/6] sbitmap: remove cleared bitmask Jens Axboe
2020-01-07 16:30 ` [PATCH 2/6] sbitmap: add batch tag retrieval Jens Axboe
2020-01-07 16:30 ` [PATCH 3/6] blk-mq: remove 'clear_ctx_on_error' Jens Axboe
2020-01-07 16:30 ` [PATCH 4/6] blk-mq: remove ctx->queue Jens Axboe
2020-01-07 16:30 ` [PATCH 5/6] blk-mq: add struct blk_mq_ctx_type Jens Axboe
2020-01-07 16:30 ` [PATCH 6/6] blk-mq: allocate tags in batches Jens Axboe
2020-01-15 12:07 ` Ming Lei
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