linux-kernel - Re: [PATCH] sched: balance_cpu to consider other cpus in its group as target of (pinned) task migration

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: <20120604143802.GB26651@linux.vnet.ibm.com>
Date:	Mon, 4 Jun 2012 20:08:02 +0530
From:	Srivatsa Vaddagiri <vatsa@...ux.vnet.ibm.com>
To:	Mike Galbraith <efault@....de>
Cc:	Peter Zijlstra <peterz@...radead.org>,
	Prashanth Nageshappa <prashanth@...ux.vnet.ibm.com>,
	mingo@...nel.org, LKML <linux-kernel@...r.kernel.org>,
	roland@...nel.org, Ingo Molnar <mingo@...e.hu>
Subject: Re: [PATCH] sched: balance_cpu to consider other cpus in its group
 as target of (pinned) task migration

* Mike Galbraith <efault@....de> [2012-06-04 16:30:34]:

> Yeah, this is true, it is a latency source and a fairness violation.
> Slow path balance consideration does make some sense to me.
> 
> But, if you have an RT requirement, you can't afford to mix unknown
> entities, nor over-commit etc.  A realtime application will assign all
> resources, so the load balancer becomes essentially unemployed.  No?
> Non critical worker-bees may be allowed to bounce around in say a
> cpuset, but none of the CPUs which do critical work will ever be
> over-committed, else application just lost the war.  In that regard,
> twiddling the load balancer to accommodate strange sounding case still
> seems wrong to me.

Btw the patch should help non-rt case as well (where a high
priority SCHED_OTHER is hogging cpu while low-priority SCHED_OTHER task
on that same cpu suffers as we choose not to move it to another
cpu (because of the way balance_cpu based load balance is written).

- vatsa

--
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/