Linux-NVME Archive on lore.kernel.org
 help / color / mirror / Atom feed
From: alex.nlnnfn@gmail.com (Alex Nln)
Subject: coalescing in polling mode in 4.9
Date: Fri, 2 Feb 2018 00:10:28 -0800	[thread overview]
Message-ID: <20180202001028.fee27cf239e3e8a5ae6bd8a4@gmail.com> (raw)

Hello,

Enabling interrupt coalescing in nvme device, kernel 4.9 
significantly reduces performance when using polling mode.
When I enable coalescing, IOPS drops from 100K to 35K and 
latency jumps from 7 usec to 25 usec.

Shouldn't we expect performance boost in polling mode when
interrupt coalescing enabled? 


Device is Intel DC P3600
Coalescing enabled:  nvme set-feature /dev/nvme0 -f 8 -v 0x00ffff
fio-2.16 file:
[global]
iodepth=1
direct=1
ioengine=pvsync2
hipri
group_reporting
time_based
blocksize=4k
norandommap=1

[job1]
rw=read
filename=/dev/nvme0n1
name=raw=sequential-read
numjobs=1
runtime=60



Thanks

             reply	other threads:[~2018-02-02  8:10 UTC|newest]

Thread overview: 12+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-02-02  8:10 Alex Nln [this message]
2018-02-05  0:15 ` coalescing in polling mode in 4.9 Alex Nln
2018-02-05 14:40   ` Sagi Grimberg
2018-02-05 15:02 ` Keith Busch
2018-02-05 15:42   ` Nitesh
2018-02-06  5:39     ` Alex Nln
2018-02-09 22:37       ` Nitesh Shetty
2018-02-10 21:08         ` Alex Nln
2018-02-12 14:53           ` Keith Busch
2018-02-06 16:29     ` Keith Busch
2018-02-07  8:27       ` Nitesh
2018-02-06  3:55   ` Alex Nln

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=20180202001028.fee27cf239e3e8a5ae6bd8a4@gmail.com \
    --to=alex.nlnnfn@gmail.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