From: Pavel Begunkov <asml.silence@gmail.com>
To: linux-block@vger.kernel.org
Cc: Jens Axboe <axboe@kernel.dk>,
linux-kernel@vger.kernel.org, linux-mm@kvack.org,
Christoph Lameter <cl@linux.com>, Tejun Heo <tj@kernel.org>,
Dennis Zhou <dennis@kernel.org>,
Pavel Begunkov <asml.silence@gmail.com>
Subject: [PATCH 0/2] optimise blk_try_enter_queue()
Date: Wed, 20 Oct 2021 21:03:17 +0100 [thread overview]
Message-ID: <cover.1634759754.git.asml.silence@gmail.com> (raw)
Kill extra rcu_read_lock/unlock() pair in blk_try_enter_queue().
Testing with io_uring (high batching) with nullblk:
Before:
3.20% io_uring [kernel.vmlinux] [k] __rcu_read_unlock
3.05% io_uring [kernel.vmlinux] [k] __rcu_read_lock
After:
2.52% io_uring [kernel.vmlinux] [k] __rcu_read_unlock
2.28% io_uring [kernel.vmlinux] [k] __rcu_read_lock
Doesn't necessarily translates into 1.4% perfofrmance improvement
but nice to have.
Pavel Begunkov (2):
percpu_ref: percpu_ref_tryget_live() version holding RCU
block: kill extra rcu lock/unlock in queue enter
block/blk-core.c | 2 +-
include/linux/percpu-refcount.h | 31 +++++++++++++++++++++----------
2 files changed, 22 insertions(+), 11 deletions(-)
--
2.33.1
next reply other threads:[~2021-10-20 20:03 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-10-20 20:03 Pavel Begunkov [this message]
2021-10-20 20:03 ` [PATCH 1/2] percpu_ref: percpu_ref_tryget_live() version holding RCU Pavel Begunkov
2021-10-20 20:10 ` Tejun Heo
2021-10-21 8:41 ` Pavel Begunkov
2021-10-20 20:03 ` [PATCH 2/2] block: kill extra rcu lock/unlock in queue enter Pavel Begunkov
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