From: Peter Zijlstra <peterz@infradead.org>
To: Raghavendra Rao Ananta <rananta@codeaurora.org>
Cc: mingo@redhat.com, acme@kernel.org,
alexander.shishkin@linux.intel.com, jolsa@redhat.com,
namhyung@kernel.org, linux-kernel@vger.kernel.org,
psodagud@codeaurora.org, tsoni@codeaurora.org
Subject: Re: [PATCH] perf: Add support for creating offline events
Date: Tue, 13 Feb 2018 19:23:51 +0100 [thread overview]
Message-ID: <20180213182351.GQ25201@hirez.programming.kicks-ass.net> (raw)
In-Reply-To: <1518217620-28458-1-git-send-email-rananta@codeaurora.org>
On Fri, Feb 09, 2018 at 03:07:00PM -0800, Raghavendra Rao Ananta wrote:
> Perf framework doesn't allow creation of hardware events if
> the requested CPU is offline. However, creation of an event
> is achievable if the event is attached to the PMU as soon
> as the CPU is online again.
>
> So, introducing a feature that could allow to create events
> even when the CPU is offline and return a success to the caller.
> If, during the time of event creation, the CPU is found offline,
> the event is moved to a new state (PERF_EVENT_STATE_DORMANT). As
> and when the CPU is know to be woken up (through hotplug notifiers),
> all the dormant events would be attached to the PMU (by
> perf_install_in_context()). If during the life time of the event,
> the CPU hasn't come online, the dormant event would just be freed.
This is horrible.. and you seem to have forgotten to explain why you
care about offline CPUs.
next prev parent reply other threads:[~2018-02-13 18:24 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-02-09 23:07 Raghavendra Rao Ananta
2018-02-12 9:43 ` Jiri Olsa
2018-02-12 17:42 ` Raghavendra Rao Ananta
2018-02-12 21:04 ` Jiri Olsa
2018-02-12 21:21 ` Jiri Olsa
2018-02-12 22:22 ` Raghavendra Rao Ananta
2018-02-13 16:08 ` Jiri Olsa
2018-02-13 18:03 ` Raghavendra Rao Ananta
2018-02-12 9:44 ` Jiri Olsa
2018-02-12 19:11 ` kbuild test robot
2018-02-13 18:23 ` Peter Zijlstra [this message]
2018-02-13 22:17 ` Sodagudi Prasad
2018-02-14 8:32 ` Peter Zijlstra
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