LKML Archive on
help / color / mirror / Atom feed
From: Paul Jackson <>
To: Max Krasnyansky <>
Subject: Re: Integrating cpusets and cpu isolation [was Re: [CPUISOL] CPU isolation extensions]
Date: Sun, 3 Feb 2008 01:53:15 -0600	[thread overview]
Message-ID: <> (raw)
In-Reply-To: <>

Max wrote:
> Paul, I actually mentioned at the beginning of my email that I did read that thread
> started by Peter. I did learn quite a bit from it :)

Ah - sorry - I missed that part.  However, I'm still getting the feeling
that there were some key points in that thread that we have not managed
to communicate successfully.

> Sounds like at this point we're in agreement that sched_load_balance is not suitable
> for what I'd like to achieve.

I don't think we're in agreement; I think we're in confusion ;)

Yes, sched_load_balance does not *directly* have anything to do with

But indirectly it is a critical element in what I think you'd like to
achieve.  It affects how the cpuset code sets up sched_domains, and
if I understand correctly, you require either (1) some sched_domains to
only contain RT tasks, or (2) some CPUs to be in no sched_domain at all.

Proper configuration of the cpuset hierarchy, including the setting of
the per-cpuset sched_load_balance flag, can provide either of these
sched_domain partitions, as desired.

> But how about making cpusets aware of the cpu_isolated_map ?

No.  That's confusing cpusets and the scheduler again.

The cpu_isolated_map is a file static variable known only within
the kernel/sched.c file; this should not change.

Presently, the boot parameter isolcpus= is just used to initialize
what CPUs are isolated at boot, and then the sched_domain partitioning,
as done in kernel/sched.c:partition_sched_domains() (the hook into
the sched code that cpusets uses) determines which CPUs are isolated
from that point forward.  I doubt that this should change either.

In that thread referenced above, did you see the part where RT is
achieved not by isolating CPUs from any scheduler, but rather by
polymorphically having several schedulers available to operate on each
sched_domain, and having RT threads self-select the RT scheduler?

                  I won't rest till it's the best ...
                  Programmer, Linux Scalability
                  Paul Jackson <> 1.940.382.4214

  reply	other threads:[~2008-02-03  7:53 UTC|newest]

Thread overview: 36+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2008-01-28  4:09 [CPUISOL] CPU isolation extensions maxk
2008-01-28  4:09 ` [PATCH] [CPUISOL] Add config options for CPU isolation maxk
2008-01-28  4:09   ` [PATCH] [CPUISOL] Export CPU isolation bits maxk
2008-01-28  4:09     ` [PATCH] [CPUISOL] Do not route IRQs to the CPUs isolated at boot maxk
2008-01-28  4:09       ` [PATCH] [CPUISOL] Support for workqueue isolation maxk
2008-01-28  4:09         ` [PATCH] [CPUISOL] Isolated CPUs should be ignored by the "stop machine" maxk
2008-01-28  9:08 ` [CPUISOL] CPU isolation extensions Peter Zijlstra
2008-01-28 14:59   ` Paul Jackson
2008-01-28 16:34     ` Steven Rostedt
2008-01-28 16:44       ` Peter Zijlstra
2008-01-28 18:54         ` Max Krasnyanskiy
2008-01-28 18:46       ` Max Krasnyanskiy
2008-01-28 19:00         ` Steven Rostedt
2008-01-28 20:22           ` Peter Zijlstra
2008-01-28 21:42             ` Max Krasnyanskiy
2008-02-05  0:32             ` CPU isolation and workqueues [was Re: [CPUISOL] CPU isolation extensions] Max Krasnyanskiy
2008-01-28 18:37     ` [CPUISOL] CPU isolation extensions Max Krasnyanskiy
2008-01-28 19:06       ` Paul Jackson
2008-01-28 21:47         ` Max Krasnyanskiy
2008-01-31 19:06         ` Integrating cpusets and cpu isolation [was Re: [CPUISOL] CPU isolation extensions] Max Krasnyanskiy
2008-02-02  6:16           ` Paul Jackson
2008-02-03  5:57             ` Max Krasnyansky
2008-02-03  7:53               ` Paul Jackson [this message]
2008-02-04  6:03                 ` Max Krasnyansky
2008-02-04 10:54                   ` Paul Jackson
2008-02-04 23:19                     ` Max Krasnyanskiy
2008-02-05  2:46                       ` Paul Jackson
2008-02-05  4:08                         ` Max Krasnyansky
2008-01-28 18:32   ` [CPUISOL] CPU isolation extensions Max Krasnyanskiy
2008-01-28 19:10     ` Paul Jackson
2008-01-28 23:41     ` Daniel Walker
2008-01-29  0:12       ` Max Krasnyanskiy
2008-01-29  1:33         ` Daniel Walker
2008-02-04  6:53           ` Max Krasnyansky
2008-01-31 12:16 ` Mark Hounschell
2008-01-31 19:13   ` Max Krasnyanskiy

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:

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \ \ \ \ \ \ \ \ \

* 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).