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From: "H. Peter Anvin" <hpa@zytor.com>
To: Peter Zijlstra <peterz@infradead.org>,
	"Waskiewicz Jr, Peter P" <peter.p.waskiewicz.jr@intel.com>
Cc: Tejun Heo <tj@kernel.org>, Thomas Gleixner <tglx@linutronix.de>,
	Ingo Molnar <mingo@redhat.com>, Li Zefan <lizefan@huawei.com>,
	"containers@lists.linux-foundation.org" 
	<containers@lists.linux-foundation.org>,
	"cgroups@vger.kernel.org" <cgroups@vger.kernel.org>,
	"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH 0/4] x86: Add Cache QoS Monitoring (CQM) support
Date: Tue, 14 Jan 2014 09:58:26 -0800	[thread overview]
Message-ID: <52D57AC2.3090109@zytor.com> (raw)
In-Reply-To: <20140113075528.GR7572@laptop.programming.kicks-ass.net>

On 01/12/2014 11:55 PM, Peter Zijlstra wrote:
> 
> The problem is, since there's a limited number of RMIDs we have to
> rotate at some point, but since changing RMIDs is nondeterministic we
> can't.
> 

This is fundamentally the crux here.  RMIDs are quite expensive for the
hardware to implement, so they are limited - but recycling them is
*very* expensive because you literally have to touch every line in the
cache.

	-hpa



  reply	other threads:[~2014-01-14 17:59 UTC|newest]

Thread overview: 35+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2014-01-03 20:34 [PATCH 0/4] x86: Add Cache QoS Monitoring (CQM) support Peter P Waskiewicz Jr
2014-01-03 20:34 ` [PATCH 1/4] x86: Add support for Cache QoS Monitoring (CQM) detection Peter P Waskiewicz Jr
2014-01-03 20:34 ` [PATCH 2/4] x86: Add Cache QoS Monitoring support to x86 perf uncore Peter P Waskiewicz Jr
2014-01-03 20:34 ` [PATCH 3/4] cgroup: Add new cacheqos cgroup subsys to support Cache QoS Monitoring Peter P Waskiewicz Jr
2014-01-03 20:34 ` [PATCH 4/4] Documentation: Add documentation for cacheqos cgroup Peter P Waskiewicz Jr
2014-01-04 16:10 ` [PATCH 0/4] x86: Add Cache QoS Monitoring (CQM) support Tejun Heo
2014-01-04 22:43   ` Waskiewicz Jr, Peter P
2014-01-04 22:50     ` Tejun Heo
2014-01-05  5:23       ` Waskiewicz Jr, Peter P
2014-01-06 11:16         ` Peter Zijlstra
2014-01-06 16:34           ` Waskiewicz Jr, Peter P
2014-01-06 16:41             ` Peter Zijlstra
2014-01-06 16:47               ` Waskiewicz Jr, Peter P
2014-01-06 17:53                 ` Peter Zijlstra
2014-01-06 18:05                   ` Waskiewicz Jr, Peter P
2014-01-06 18:06                 ` Peter Zijlstra
2014-01-06 20:10                   ` Waskiewicz Jr, Peter P
2014-01-06 21:26                     ` Peter Zijlstra
2014-01-06 21:48                       ` Waskiewicz Jr, Peter P
2014-01-06 22:12                         ` Peter Zijlstra
2014-01-06 22:45                           ` Waskiewicz Jr, Peter P
2014-01-07  8:34                             ` Peter Zijlstra
2014-01-07 15:15                               ` Waskiewicz Jr, Peter P
2014-01-07 21:12                                 ` Peter Zijlstra
2014-01-10 18:55                                   ` Waskiewicz Jr, Peter P
2014-01-13  7:55                                     ` Peter Zijlstra
2014-01-14 17:58                                       ` H. Peter Anvin [this message]
2014-01-27 17:34                                         ` Peter Zijlstra
2014-02-18 17:29                                           ` Waskiewicz Jr, Peter P
2014-02-18 19:35                                             ` Peter Zijlstra
2014-02-18 19:54                                               ` Waskiewicz Jr, Peter P
2014-02-20 16:58                                                 ` Peter Zijlstra
2014-01-14 20:46                                       ` Waskiewicz Jr, Peter P
2014-01-06 11:08 ` Peter Zijlstra
2014-01-06 16:42   ` Waskiewicz Jr, Peter P

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