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From: Srivatsa Vaddagiri <vatsa@in.ibm.com>
To: Paul Menage <menage@google.com>
Cc: bharata@linux.vnet.ibm.com, linux-kernel@vger.kernel.org,
	Dhaval Giani <dhaval@linux.vnet.ibm.com>,
	Balbir Singh <balbir@linux.vnet.ibm.com>,
	Vaidyanathan Srinivasan <svaidy@linux.vnet.ibm.com>,
	Gautham R Shenoy <ego@in.ibm.com>, Ingo Molnar <mingo@elte.hu>,
	Peter Zijlstra <a.p.zijlstra@chello.nl>,
	Pavel Emelyanov <xemul@openvz.org>, Avi Kivity <avi@redhat.com>,
	kvm@vger.kernel.org,
	Linux Containers <containers@lists.linux-foundation.org>,
	Herbert Poetzl <herbert@13thfloor.at>
Subject: Re: [RFC] CPU hard limits
Date: Fri, 5 Jun 2009 17:02:17 +0530	[thread overview]
Message-ID: <20090605113217.GA20786@in.ibm.com> (raw)
In-Reply-To: <6599ad830906050153i1afd104fqe70f681317349142@mail.gmail.com>

On Fri, Jun 05, 2009 at 01:53:15AM -0700, Paul Menage wrote:
> This claim (and the subsequent long thread it generated on how limits
> can provide guarantees) confused me a bit.
> 
> Why do we need limits to provide guarantees when we can already
> provide guarantees via shares?

I think the interval over which we need guarantee matters here. Shares
can generally provide guaranteed share of resource over longer (sometimes
minutes) intervals. For high-priority bursty workloads, the latency in 
achieving guaranteed resource usage matters. By having hard-limits, we are 
"reserving" (potentially idle) slots where the high-priority group can run and 
claim its guaranteed share almost immediately.

- vatsa

  parent reply	other threads:[~2009-06-05 11:32 UTC|newest]

Thread overview: 107+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2009-06-04  5:36 [RFC] CPU hard limits Bharata B Rao
2009-06-04 12:19 ` Avi Kivity
2009-06-04 21:32   ` Mike Waychison
2009-06-05  3:03   ` Bharata B Rao
2009-06-05  3:33     ` Avi Kivity
2009-06-05  4:37       ` Balbir Singh
2009-06-05  4:44         ` Avi Kivity
2009-06-05  4:49           ` Balbir Singh
     [not found]             ` <20090605044946.GA11755-SINUvgVNF2CyUtPGxGje5AC/G2K4zDHf@public.gmane.org>
2009-06-05  5:09               ` Chris Friesen
2009-06-05  5:10               ` Balbir Singh
2009-06-05  5:16               ` Avi Kivity
2009-06-05  5:09             ` Chris Friesen
2009-06-05  5:13               ` Balbir Singh
     [not found]               ` <4A28A882.8070503-ZIRUuHA3oDzQT0dZR+AlfA@public.gmane.org>
2009-06-05  5:13                 ` Balbir Singh
2009-06-05  5:10             ` Balbir Singh
     [not found]               ` <20090605051050.GB11755-SINUvgVNF2CyUtPGxGje5AC/G2K4zDHf@public.gmane.org>
2009-06-05  5:21                 ` Avi Kivity
2009-06-05  5:21               ` Avi Kivity
     [not found]                 ` <4A28AB67.7040800-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>
2009-06-05  5:27                   ` Balbir Singh
2009-06-05  5:27                 ` Balbir Singh
     [not found]                   ` <20090605052755.GE11755-SINUvgVNF2CyUtPGxGje5AC/G2K4zDHf@public.gmane.org>
2009-06-05  5:31                     ` Bharata B Rao
2009-06-05  6:03                     ` Avi Kivity
2009-06-05  5:31                   ` Bharata B Rao
     [not found]                     ` <20090605053159.GB3872-xthvdsQ13ZrQT0dZR+AlfA@public.gmane.org>
2009-06-05  6:01                       ` Avi Kivity
2009-06-05  9:24                       ` Balbir Singh
2009-06-05  6:01                     ` Avi Kivity
     [not found]                       ` <4A28B4CE.4010004-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>
2009-06-05  8:16                         ` Bharata B Rao
2009-06-05  8:16                           ` Bharata B Rao
2009-06-07  6:04                           ` Avi Kivity
2009-06-07 16:14                             ` Bharata B Rao
     [not found]                             ` <4A2B5881.9060204-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>
2009-06-07 16:14                               ` Bharata B Rao
     [not found]                           ` <20090605081651.GD3872-xthvdsQ13ZrQT0dZR+AlfA@public.gmane.org>
2009-06-07  6:04                             ` Avi Kivity
2009-06-05  9:39                         ` Balbir Singh
2009-06-05  9:39                       ` Balbir Singh
2009-06-05 13:14                         ` Avi Kivity
     [not found]                           ` <4A291A2F.3090201-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>
2009-06-05 13:42                             ` Balbir Singh
2009-06-05 13:42                               ` Balbir Singh
     [not found]                               ` <661de9470906050642s7774d601l53e366c77ffa7475-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org>
2009-06-07  6:09                                 ` Avi Kivity
2009-06-07  6:09                               ` Avi Kivity
2009-06-05 14:54                             ` Chris Friesen
2009-06-05 14:54                           ` Chris Friesen
     [not found]                             ` <4A293196.2060006-ZIRUuHA3oDzQT0dZR+AlfA@public.gmane.org>
2009-06-07  6:10                               ` Avi Kivity
2009-06-07  6:10                             ` Avi Kivity
     [not found]                         ` <20090605093947.GJ11755-SINUvgVNF2CyUtPGxGje5AC/G2K4zDHf@public.gmane.org>
2009-06-05 13:14                           ` Avi Kivity
2009-06-05  9:24                     ` Balbir Singh
2009-06-05  6:03                   ` Avi Kivity
     [not found]                     ` <4A28B539.3050001-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>
2009-06-05  6:32                       ` Bharata B Rao
2009-06-05  6:32                     ` Bharata B Rao
2009-06-05 12:57                       ` Avi Kivity
     [not found]                       ` <20090605063243.GC3872-xthvdsQ13ZrQT0dZR+AlfA@public.gmane.org>
2009-06-05 12:57                         ` Avi Kivity
2009-06-05  5:16             ` Avi Kivity
     [not found]               ` <4A28AA25.4050206-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>
2009-06-05  5:20                 ` Balbir Singh
2009-06-05  5:20               ` Balbir Singh
     [not found]           ` <4A28A2AB.3060108-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>
2009-06-05  4:49             ` Balbir Singh
     [not found]         ` <661de9470906042137u603e2997n80c270bf7f6191ad-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org>
2009-06-05  4:44           ` Avi Kivity
     [not found]       ` <4A28921C.6010802-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>
2009-06-05  4:37         ` Balbir Singh
     [not found]     ` <20090605030309.GA3872-xthvdsQ13ZrQT0dZR+AlfA@public.gmane.org>
2009-06-05  3:33       ` Avi Kivity
     [not found]   ` <4A27BBCA.5020606-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>
2009-06-04 21:32     ` Mike Waychison
2009-06-05  3:03     ` Bharata B Rao
2009-06-05  3:07     ` Balbir Singh
2009-06-05  3:07   ` Balbir Singh
     [not found] ` <20090604053649.GA3701-xthvdsQ13ZrQT0dZR+AlfA@public.gmane.org>
2009-06-04 12:19   ` Avi Kivity
2009-06-05  8:53   ` Paul Menage
2009-06-05  8:53 ` Paul Menage
2009-06-05  9:27   ` Bharata B Rao
2009-06-05  9:32     ` Paul Menage
     [not found]       ` <6599ad830906050232n11aa30d8xfcda0a279a482f32-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org>
2009-06-05  9:48         ` Dhaval Giani
2009-06-05  9:48       ` Dhaval Giani
     [not found]         ` <20090605094811.GD4601-23VcF4HTsmIX0ybBhKVfKdBPR1lH4CV8@public.gmane.org>
2009-06-05  9:51           ` Paul Menage
2009-06-05  9:51         ` Paul Menage
2009-06-05  9:59           ` Dhaval Giani
     [not found]             ` <20090605095931.GE4601-23VcF4HTsmIX0ybBhKVfKdBPR1lH4CV8@public.gmane.org>
2009-06-05 10:03               ` Paul Menage
2009-06-05 10:03             ` Paul Menage
2009-06-08  8:50               ` Pavel Emelyanov
     [not found]               ` <6599ad830906050303r404c325anc60ded4f45a50b95-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org>
2009-06-08  8:50                 ` Pavel Emelyanov
     [not found]           ` <6599ad830906050251h18f4e037h182f61aa80a5b046-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org>
2009-06-05  9:59             ` Dhaval Giani
     [not found]     ` <20090605092733.GA27486-xthvdsQ13ZrQT0dZR+AlfA@public.gmane.org>
2009-06-05  9:32       ` Paul Menage
     [not found]   ` <6599ad830906050153i1afd104fqe70f681317349142-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org>
2009-06-05  9:27     ` Bharata B Rao
2009-06-05  9:36     ` Balbir Singh
2009-06-05 11:32     ` Srivatsa Vaddagiri
2009-06-05 13:02     ` Avi Kivity
2009-06-05  9:36   ` Balbir Singh
     [not found]     ` <20090605093625.GI11755-SINUvgVNF2CyUtPGxGje5AC/G2K4zDHf@public.gmane.org>
2009-06-05  9:48       ` Paul Menage
2009-06-05  9:48         ` Paul Menage
     [not found]         ` <6599ad830906050248m2c569e5bx44fb3bbddf46f8b1-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org>
2009-06-05  9:55           ` Balbir Singh
2009-06-05  9:55         ` Balbir Singh
2009-06-05  9:57           ` Paul Menage
     [not found]           ` <20090605095527.GM11755-SINUvgVNF2CyUtPGxGje5AC/G2K4zDHf@public.gmane.org>
2009-06-05  9:57             ` Paul Menage
2009-06-05 10:02             ` Paul Menage
2009-06-05 10:02           ` Paul Menage
2009-06-05 11:32   ` Srivatsa Vaddagiri [this message]
     [not found]     ` <20090605113217.GA20786-xthvdsQ13ZrQT0dZR+AlfA@public.gmane.org>
2009-06-05 12:18       ` Paul Menage
2009-06-05 14:44       ` Chris Friesen
2009-06-05 12:18     ` Paul Menage
     [not found]       ` <6599ad830906050518t6cd7d477h36a187f2eaf55578-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org>
2009-06-07 10:11         ` Srivatsa Vaddagiri
2009-06-07 10:11           ` Srivatsa Vaddagiri
2009-06-07 15:35           ` Balbir Singh
2009-06-08  4:37             ` Srivatsa Vaddagiri
     [not found]             ` <661de9470906070835l383cd388h67e40a31be07aef6-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org>
2009-06-08  4:37               ` Srivatsa Vaddagiri
     [not found]           ` <20090607101120.GB16211-xthvdsQ13ZrQT0dZR+AlfA@public.gmane.org>
2009-06-07 15:35             ` Balbir Singh
2009-06-05 14:44     ` Chris Friesen
2009-06-05 13:02   ` Avi Kivity
2009-06-05 13:43     ` Dhaval Giani
     [not found]       ` <20090605134320.GA3994-23VcF4HTsmIX0ybBhKVfKdBPR1lH4CV8@public.gmane.org>
2009-06-05 14:45         ` Chris Friesen
2009-06-05 14:45       ` Chris Friesen
     [not found]     ` <4A291753.7090205-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>
2009-06-05 13:43       ` Dhaval Giani
2009-06-05  9:02 ` Reinhard Tartler
  -- strict thread matches above, loose matches on Subject: below --
2009-06-04  5:36 Bharata B Rao

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