linux-kernel - Re: [RFC] sched_tick with interrupts enabled

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-Id: <20061019191623.5279bc77.kamezawa.hiroyu@jp.fujitsu.com>
Date:	Thu, 19 Oct 2006 19:16:23 +0900
From:	KAMEZAWA Hiroyuki <kamezawa.hiroyu@...fujitsu.com>
To:	"Siddha, Suresh B" <suresh.b.siddha@...el.com>
Cc:	clameter@....com, nickpiggin@...oo.com.au,
	suresh.b.siddha@...el.com, mingo@...e.hu, pwil3058@...pond.net.au,
	linux-kernel@...r.kernel.org,
	"kaneshige.kenji@...t.fujitsu.com" <kaneshige.kenji@...t.fujitsu.com>
Subject: Re: [RFC] sched_tick with interrupts enabled

On Wed, 18 Oct 2006 19:19:00 -0700
"Siddha, Suresh B" <suresh.b.siddha@...el.com> wrote:

> On Wed, Oct 18, 2006 at 02:59:07PM -0700, Christoph Lameter wrote:
> > load_balancing has the potential of running for some time if f.e.
> > sched_domains for a system with 1024 processors have to be balanced.
> > We currently do all of that with interrupts disabled. So we may be unable
> > to service interrupts for some time. Most of that time is potentially
> > spend in rebalance_tick.
> 
> Did you see an issue because of this or just theoretical?
> 

IIRC, Fujitsu's 64-cpu ia64/SMP system sufferred from this issue *in older kernel*. 
Now, we avoid it by creating NUMA nodes and dividing scheduler domains.

Situation was...:
5 runnable processes which were pinned to a cpu in a 64cpu system.
the system was always rebalanced and seems to be hanged.

-Kame

-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/