From: "Rogozhkin, Dmitry V" <dmitry.v.rogozhkin@intel.com>
To: "peterz@infradead.org" <peterz@infradead.org>
Cc: "Intel-gfx@lists.freedesktop.org" <Intel-gfx@lists.freedesktop.org>
Subject: Re: [RFC 04/10] drm/i915: Expose a PMU interface for perf queries
Date: Wed, 13 Sep 2017 23:05:37 +0000 [thread overview]
Message-ID: <1505315006.6966.22.camel@intel.com> (raw)
In-Reply-To: <20170829192152.GB32112@worktop.programming.kicks-ass.net>
On Tue, 2017-08-29 at 21:21 +0200, Peter Zijlstra wrote:
> On Tue, Aug 29, 2017 at 07:16:31PM +0000, Rogozhkin, Dmitry V wrote:
> > > Pretty strict, people tend to get fairly upset every time we leak stuff.
> > > In fact Debian and Android carry a perf_event_paranoid patch that
> > > default disables _everything_ :-(
> >
> > Can you say more on that for Debian and Android? What exactly they do?
> > What is the value of perf_event_paranoid there? They disable everything
> > even for root and CAP_SYS_ADMIN? But still they don't remove this from
> > kernel on compilation stage, right? So users can explicitly change
> > perf_event_paranoid to the desired value?
>
> They introduce (and default to) perf_event_paranoid = 3. Which
> disallows everything for unpriv user, root can still do things IIRC, I'd
> have to dig out the patch.
>
> This way apps have no access to the syscall, but you can enable it using
> ADB by lowering the setting. So developers still have access, but
> regular apps do not.
>
Hi, Peter.
How you would feel about the following idea (or close to it):
1. We introduce one more level for perf_event_paranoid=4 (or =3, I am
not sure whether Debian/Android =3 is considered uAPI) which would mean:
"disallow kernel profiling for unpriv, but let individual kernel modules
to have their own settings".
2. We will have i915 PMU custom setting
"/sys/module/i915/parameters/perf_event_paranoid" which will be in
effect only if global perf_event_paranoid=4 (or =3) and prevail over a
global setting
Would anything like that be acceptable upstream? This would permit
customers to configure i915 PMU support for unpriv users separately from
the rest of PMU subsystem.
Regards,
Dmitry.
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next prev parent reply other threads:[~2017-09-13 23:05 UTC|newest]
Thread overview: 32+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-08-02 12:32 [RFC v2 00/10] i915 PMU and engine busy stats Tvrtko Ursulin
2017-08-02 12:32 ` [RFC 01/10] drm/i915: Convert intel_rc6_residency_us to ns Tvrtko Ursulin
2017-08-02 12:32 ` [RFC 02/10] drm/i915: Add intel_energy_uJ Tvrtko Ursulin
2017-08-02 12:32 ` [RFC 03/10] drm/i915: Extract intel_get_cagf Tvrtko Ursulin
2017-08-02 12:32 ` [RFC 04/10] drm/i915: Expose a PMU interface for perf queries Tvrtko Ursulin
2017-08-02 13:00 ` Tvrtko Ursulin
2017-08-12 2:15 ` Rogozhkin, Dmitry V
2017-08-22 18:17 ` Peter Zijlstra
2017-08-23 17:51 ` Rogozhkin, Dmitry V
2017-08-23 18:01 ` Peter Zijlstra
2017-08-23 18:40 ` Rogozhkin, Dmitry V
2017-08-23 18:04 ` Peter Zijlstra
2017-08-23 18:38 ` Rogozhkin, Dmitry V
2017-08-23 19:28 ` Peter Zijlstra
2017-08-23 18:05 ` Peter Zijlstra
2017-08-23 18:22 ` Peter Zijlstra
2017-08-23 19:00 ` Rogozhkin, Dmitry V
2017-08-23 19:33 ` Peter Zijlstra
2017-08-28 22:57 ` Rogozhkin, Dmitry V
2017-08-29 9:30 ` Peter Zijlstra
2017-08-29 19:16 ` Rogozhkin, Dmitry V
2017-08-29 19:21 ` Peter Zijlstra
2017-09-13 23:05 ` Rogozhkin, Dmitry V [this message]
2017-09-20 20:14 ` Rogozhkin, Dmitry V
2017-10-02 21:28 ` Rogozhkin, Dmitry V
2017-08-02 12:32 ` [RFC 05/10] drm/i915/pmu: Suspend sampling when GPU is idle Tvrtko Ursulin
2017-08-02 12:32 ` [RFC 06/10] drm/i915: Wrap context schedule notification Tvrtko Ursulin
2017-08-02 12:32 ` [RFC 07/10] drm/i915: Engine busy time tracking Tvrtko Ursulin
2017-08-02 12:32 ` [RFC 08/10] drm/i915: Export engine busy stats in debugfs Tvrtko Ursulin
2017-08-02 12:32 ` [RFC 09/10] drm/i915/pmu: Wire up engine busy stats to PMU Tvrtko Ursulin
2017-08-02 12:39 ` [RFC 10/10] drm/i915: Gate engine stats collection with a static key Tvrtko Ursulin
2017-08-02 12:56 ` ✗ Fi.CI.BAT: warning for i915 PMU and engine busy stats (rev2) Patchwork
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