From: luferry <luferry@163.com>
To: Jens Axboe <axboe@kernel.dk>
Cc: Ming Lei <ming.lei@redhat.com>, Christoph Hellwig <hch@lst.de>,
xuyun <luferry@163.com>,
linux-block@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: [PATCH] block/mq: blk map queues by core id
Date: Fri, 22 Mar 2019 18:09:49 +0800 [thread overview]
Message-ID: <20190322100949.5555-1-luferry@163.com> (raw)
under virtual machine environment, cpu topology may differ from normal
physical server.
for example (machine with 4 cores, 2 threads per core):
normal physical server:
core-id thread-0-id thread-1-id
0 0 4
1 1 5
2 2 6
3 3 7
virtual machine:
core-id thread-0-id thread-1-id
0 0 1
1 2 3
2 4 5
3 6 7
When attach disk with two queues, all the even numbered cpus will be
mapped to queue 0. Under virtual machine, all the cpus is followed by
its sibling cpu.Before this patch, all the odd numbered cpus will also
be mapped to queue 0, can cause serious imbalance.this will lead to
performance impact on system IO
So suggest to allocate cpu map by core id, this can be more currency
Signed-off-by: luferry <luferry@163.com>
---
block/blk-mq-cpumap.c | 9 +++++----
1 file changed, 5 insertions(+), 4 deletions(-)
diff --git a/block/blk-mq-cpumap.c b/block/blk-mq-cpumap.c
index 03a534820271..4125e8e77679 100644
--- a/block/blk-mq-cpumap.c
+++ b/block/blk-mq-cpumap.c
@@ -35,7 +35,7 @@ int blk_mq_map_queues(struct blk_mq_queue_map *qmap)
{
unsigned int *map = qmap->mq_map;
unsigned int nr_queues = qmap->nr_queues;
- unsigned int cpu, first_sibling;
+ unsigned int cpu, first_sibling, core = 0;
for_each_possible_cpu(cpu) {
/*
@@ -48,9 +48,10 @@ int blk_mq_map_queues(struct blk_mq_queue_map *qmap)
map[cpu] = cpu_to_queue_index(qmap, nr_queues, cpu);
} else {
first_sibling = get_first_sibling(cpu);
- if (first_sibling == cpu)
- map[cpu] = cpu_to_queue_index(qmap, nr_queues, cpu);
- else
+ if (first_sibling == cpu) {
+ map[cpu] = cpu_to_queue_index(qmap, nr_queues, core);
+ core++;
+ } else
map[cpu] = map[first_sibling];
}
}
--
2.14.1.40.g8e62ba1
next reply other threads:[~2019-03-22 10:10 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-03-22 10:09 luferry [this message]
2019-03-22 11:53 ` [PATCH] block/mq: blk map queues by core id Dongli Zhang
2019-03-22 11:58 ` Dongli Zhang
2019-03-23 6:34 ` luferry
2019-03-23 11:14 ` Dongli Zhang
2019-03-25 9:49 ` luferry
2019-03-25 9:53 ` luferry
2019-03-25 13:53 ` Dongli Zhang
2019-03-25 15:17 ` luferry
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20190322100949.5555-1-luferry@163.com \
--to=luferry@163.com \
--cc=axboe@kernel.dk \
--cc=hch@lst.de \
--cc=linux-block@vger.kernel.org \
--cc=linux-kernel@vger.kernel.org \
--cc=ming.lei@redhat.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).