From: Daniel Bristot de Oliveira <bristot@redhat.com>
To: "Ananyev, Konstantin" <konstantin.ananyev@intel.com>,
Adrien Mazarguil <adrien.mazarguil@6wind.com>,
Marcelo Tosatti <mtosatti@redhat.com>
Cc: "dev@dpdk.org" <dev@dpdk.org>, Luiz Capitulino <lcapitulino@redhat.com>
Subject: Re: [dpdk-dev] [PATCH] testpmd: add nanosleep in main loop
Date: Fri, 10 Nov 2017 11:42:56 +0100 [thread overview]
Message-ID: <ffb7ed09-e943-8a16-1be0-74e2ac3ce788@redhat.com> (raw)
In-Reply-To: <2601191342CEEE43887BDE71AB9772585FABBC64@irsmsx105.ger.corp.intel.com>
On 11/10/2017 11:14 AM, Ananyev, Konstantin wrote:
> Agree with Adrian here - the patch doesn't fix the problem in any case,
I would agree with you if it were possible to assume one can fully
isolate a CPU on Linux... but it is not...
This:
https://lwn.net/Articles/659490/
is still an open issue, and the reason why it is an open issue is the
kernel threads that need to run on every CPU, mainly when using the
PREEMPT_RT, which turns almost everything on threads.
> while introducing an unnecessary slowdown in testpmd iofwd mode.
> Please think up some other approach.
The other approach is to increase the priority of all other threads that
run on the isolate CPU. But that is not a good idea at all, as the other
threads might preempt the busy-loop thread at the worst possible moment.
Using the knowledge of the thread about when it is the best time to give
a chance for other threads to run would be a smarter decision.
-- Daniel
next prev parent reply other threads:[~2017-11-10 10:42 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-11-10 6:02 Marcelo Tosatti
2017-11-10 9:12 ` Adrien Mazarguil
2017-11-10 10:13 ` Daniel Bristot de Oliveira
2017-11-10 10:14 ` Ananyev, Konstantin
2017-11-10 10:42 ` Daniel Bristot de Oliveira [this message]
2017-11-10 11:14 ` Bruce Richardson
2017-11-10 13:51 ` Luiz Capitulino
2017-11-11 3:59 ` Marcelo Tosatti
2017-11-11 4:01 ` Marcelo Tosatti
2017-11-11 3:54 ` Marcelo Tosatti
2017-11-11 3:49 ` Marcelo Tosatti
2017-11-12 23:14 ` Ananyev, Konstantin
2017-11-13 18:01 ` Marcelo Tosatti
2017-11-11 3:45 ` Marcelo Tosatti
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=ffb7ed09-e943-8a16-1be0-74e2ac3ce788@redhat.com \
--to=bristot@redhat.com \
--cc=adrien.mazarguil@6wind.com \
--cc=dev@dpdk.org \
--cc=konstantin.ananyev@intel.com \
--cc=lcapitulino@redhat.com \
--cc=mtosatti@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).