From: Jens Axboe <axboe@fb.com>
To: Keith Busch <keith.busch@intel.com>
Cc: "Matias Bjørling" <m@bjorling.me>,
"Matthew Wilcox" <willy@linux.intel.com>,
"sbradshaw@micron.com" <sbradshaw@micron.com>,
"tom.leiming@gmail.com" <tom.leiming@gmail.com>,
"hch@infradead.org" <hch@infradead.org>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
"linux-nvme@lists.infradead.org" <linux-nvme@lists.infradead.org>
Subject: Re: [PATCH v7] NVMe: conversion to blk-mq
Date: Fri, 13 Jun 2014 15:28:58 -0600 [thread overview]
Message-ID: <539B6D1A.3010602@fb.com> (raw)
In-Reply-To: <alpine.LRH.2.03.1406131307330.4699@AMR>
On 06/13/2014 01:22 PM, Keith Busch wrote:
> One performance oddity we observe is that servicing the interrupt on the
> thread sibling of the core that submitted the I/O is the worst performing
> cpu you can chose; it's actually better to use a different core on the
> same node. At least that's true as long as you're not utilizing the cpus
> for other work, so YMMV.
This doesn't match what I see here. Just ran some test cases - both
sync, and higher QD. For sync performance, core or thread sibling is the
best choice, other CPUs next. That is pretty logical.
For a more loaded run, thread sibling ends up being a better choice than
core, since core runs out of steam (255K vs 275K here). And thread
sibling is still a marginally better choice than some other core on the
same node.
Which pretty much matches my expectations of what the best mappings
would be.
prev parent reply other threads:[~2014-06-13 21:29 UTC|newest]
Thread overview: 26+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-06-10 9:20 [PATCH v7] conversion to blk-mq Matias Bjørling
2014-06-10 9:20 ` [PATCH v7] NVMe: " Matias Bjørling
2014-06-10 15:51 ` Keith Busch
2014-06-10 16:19 ` Jens Axboe
2014-06-10 19:29 ` Keith Busch
2014-06-10 19:58 ` Jens Axboe
2014-06-10 21:10 ` Keith Busch
2014-06-10 21:14 ` Jens Axboe
2014-06-10 21:21 ` Keith Busch
2014-06-10 21:33 ` Matthew Wilcox
2014-06-11 16:54 ` Jens Axboe
2014-06-11 17:09 ` Matthew Wilcox
2014-06-11 22:22 ` Matias Bjørling
2014-06-11 22:51 ` Keith Busch
2014-06-12 14:32 ` Matias Bjørling
2014-06-12 16:24 ` Keith Busch
2014-06-13 0:06 ` Keith Busch
2014-06-13 14:07 ` Jens Axboe
2014-06-13 15:05 ` Keith Busch
2014-06-13 15:11 ` Jens Axboe
2014-06-13 15:16 ` Keith Busch
2014-06-13 18:14 ` Jens Axboe
2014-06-13 19:22 ` Keith Busch
2014-06-13 19:29 ` Jens Axboe
2014-06-13 20:56 ` Jens Axboe
2014-06-13 21:28 ` Jens Axboe [this message]
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