From: Peter Zijlstra <peterz@infradead.org>
To: Matt Fleming <matt@console-pimps.org>
Cc: Ingo Molnar <mingo@kernel.org>, Jiri Olsa <jolsa@redhat.com>,
Arnaldo Carvalho de Melo <acme@kernel.org>,
Andi Kleen <andi@firstfloor.org>,
Thomas Gleixner <tglx@linutronix.de>,
linux-kernel@vger.kernel.org, "H. Peter Anvin" <hpa@zytor.com>,
Kanaka Juvva <kanaka.d.juvva@intel.com>,
Matt Fleming <matt.fleming@intel.com>
Subject: Re: [PATCH v3 10/11] perf/x86/intel: Perform rotation on Intel CQM RMIDs
Date: Fri, 7 Nov 2014 13:20:52 +0100 [thread overview]
Message-ID: <20141107122052.GD3337@twins.programming.kicks-ass.net> (raw)
In-Reply-To: <1415276602-10337-11-git-send-email-matt@console-pimps.org>
On Thu, Nov 06, 2014 at 12:23:21PM +0000, Matt Fleming wrote:
> +/*
> + * If we fail to assign a new RMID for intel_cqm_rotation_rmid because
> + * cachelines are still tagged with RMIDs in limbo, we progressively
> + * increment the threshold until we find an RMID in limbo with <=
> + * __intel_cqm_threshold lines tagged. This is designed to mitigate the
> + * problem where cachelines tagged with an RMID are not steadily being
> + * evicted.
> + *
> + * On successful rotations we decrease the threshold back towards zero.
> + *
> + * __intel_cqm_max_threshold provides an upper bound on the threshold,
> + * and is measured in bytes because it's exposed to userland.
> + */
> +static unsigned int __intel_cqm_threshold;
> +static unsigned int __intel_cqm_max_threshold = -1;
Should we initialize that to a finite value? Surely results are absolute
crap if we do indeed reach that max?
next prev parent reply other threads:[~2014-11-07 12:21 UTC|newest]
Thread overview: 29+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-11-06 12:23 [PATCH v3 00/11] perf: Intel Cache QoS Monitoring support Matt Fleming
2014-11-06 12:23 ` [PATCH 01/11] perf tools: Parse event per-package info files Matt Fleming
2014-11-06 12:23 ` [PATCH 02/11] perf tools: Implement snapshot event file logic Matt Fleming
2014-11-06 12:23 ` [PATCH 03/11] perf: Make perf_cgroup_from_task() global Matt Fleming
2014-11-06 12:23 ` [PATCH 04/11] perf: Add ->count() function to read per-package counters Matt Fleming
2014-11-06 12:23 ` [PATCH v3 05/11] perf: Move cgroup init before PMU ->event_init() Matt Fleming
2014-11-06 12:23 ` [PATCH 06/11] x86: Add support for Intel Cache QoS Monitoring (CQM) detection Matt Fleming
2014-11-06 12:23 ` [PATCH v3 07/11] perf/x86/intel: Add Intel Cache QoS Monitoring support Matt Fleming
2014-11-06 12:23 ` [PATCH 08/11] perf/x86/intel: Implement LRU monitoring ID allocation for CQM Matt Fleming
2014-11-06 12:23 ` [PATCH 09/11] perf/x86/intel: Support task events with Intel CQM Matt Fleming
2014-11-07 9:08 ` Peter Zijlstra
2014-11-07 10:09 ` Matt Fleming
2014-11-07 11:22 ` Peter Zijlstra
2014-11-06 12:23 ` [PATCH v3 10/11] perf/x86/intel: Perform rotation on Intel CQM RMIDs Matt Fleming
2014-11-07 12:06 ` Peter Zijlstra
2014-11-10 20:43 ` Matt Fleming
2014-11-10 20:58 ` Peter Zijlstra
2014-11-07 12:18 ` Peter Zijlstra
2014-11-10 20:50 ` Matt Fleming
2014-11-07 12:20 ` Peter Zijlstra [this message]
2014-11-10 20:56 ` Matt Fleming
2014-11-10 21:08 ` Peter Zijlstra
2014-11-07 12:34 ` Peter Zijlstra
2014-11-07 12:38 ` Peter Zijlstra
2014-11-14 12:35 ` Matt Fleming
2014-11-10 21:31 ` Matt Fleming
2014-11-11 9:37 ` Peter Zijlstra
2014-11-07 12:58 ` Peter Zijlstra
2014-11-06 12:23 ` [PATCH 11/11] perf/x86/intel: Enable conflicting event scheduling for CQM Matt Fleming
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