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 v2 0/2] optimise blk_try_enter_queue()
Date: Thu, 21 Oct 2021 14:30:50 +0100 [thread overview]
Message-ID: <cover.1634822969.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.
v2: rcu_read_lock_held() warning (Tejun)
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 | 33 +++++++++++++++++++++++----------
2 files changed, 24 insertions(+), 11 deletions(-)
--
2.33.1
next reply other threads:[~2021-10-21 13:30 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-10-21 13:30 Pavel Begunkov [this message]
2021-10-21 13:30 ` [PATCH v2 1/2] percpu_ref: percpu_ref_tryget_live() version holding RCU Pavel Begunkov
2021-10-21 14:01 ` Dennis Zhou
2021-10-22 9:22 ` Pavel Begunkov
2021-10-22 19:22 ` Dennis Zhou
2021-10-21 13:30 ` [PATCH v2 2/2] block: kill extra rcu lock/unlock in queue enter Pavel Begunkov
2021-10-21 14:37 ` [PATCH v2 0/2] optimise blk_try_enter_queue() Jens Axboe
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