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* [PATCH 0/2] percpu_ref & block: reduce memory footprint of percpu_ref in fast path
@ 2020-08-25 10:12 Ming Lei
  2020-08-25 10:12 ` [PATCH 1/2] percpu_ref: " Ming Lei
  2020-08-25 10:12 ` [PATCH 2/2] block: move 'q_usage_counter' into front of 'request_queue' Ming Lei
  0 siblings, 2 replies; 4+ messages in thread
From: Ming Lei @ 2020-08-25 10:12 UTC (permalink / raw)
  To: linux-kernel, linux-block
  Cc: Ming Lei, Sagi Grimberg, Tejun Heo, Christoph Hellwig,
	Jens Axboe, Bart Van Assche

Hi,

The 1st patch removes memory footprint of percpu_ref in fast path
from 7 words to 2 words, since it is often used in fast path and
embedded in user struct.

The 2nd patch moves .q_usage_counter to 1st cacheline of
'request_queue'.

Simple test on null_blk shows ~2% IOPS boost on one 16cores(two threads
per core) machine, dual socket/numa.


Ming Lei (2):
  percpu_ref: reduce memory footprint of percpu_ref in fast path
  block: move 'q_usage_counter' into front of 'request_queue'

 drivers/infiniband/sw/rdmavt/mr.c |   2 +-
 include/linux/blkdev.h            |   3 +-
 include/linux/percpu-refcount.h   |  43 +++++++++----
 lib/percpu-refcount.c             | 101 ++++++++++++++++++++----------
 4 files changed, 101 insertions(+), 48 deletions(-)

Cc: Sagi Grimberg <sagi@grimberg.me>
Cc: Tejun Heo <tj@kernel.org>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: Bart Van Assche <bvanassche@acm.org>
-- 
2.25.2


^ permalink raw reply	[flat|nested] 4+ messages in thread

end of thread, other threads:[~2020-08-31  9:50 UTC | newest]

Thread overview: 4+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2020-08-25 10:12 [PATCH 0/2] percpu_ref & block: reduce memory footprint of percpu_ref in fast path Ming Lei
2020-08-25 10:12 ` [PATCH 1/2] percpu_ref: " Ming Lei
2020-08-31  9:48   ` [percpu_ref] 13f0f97539: blktests.block.027.fail kernel test robot
2020-08-25 10:12 ` [PATCH 2/2] block: move 'q_usage_counter' into front of 'request_queue' Ming Lei

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