From: Andi Kleen <andi@firstfloor.org>
To: Daniel John FitzGerald <daniel.j.fitzgerald@gmail.com>
Cc: linux-perf-users@vger.kernel.org
Subject: Re: perf_event sampling a multithreaded process - ioctl with PERF_EVENT_IOC_SET_OUTPUT fails
Date: Wed, 19 Apr 2017 08:46:23 -0700 [thread overview]
Message-ID: <877f2go0xc.fsf@firstfloor.org> (raw)
In-Reply-To: <d7635c6e-1d12-52d7-6b9f-b7c08d3a451f@gmail.com> (Daniel John FitzGerald's message of "Wed, 19 Apr 2017 11:15:20 -0400")
Daniel John FitzGerald <daniel.j.fitzgerald@gmail.com> writes:
>
> The problem that I am running into is that whenever I attempt to call
> ioctl() with PERF_EVENT_IOC_SET_OUTPUT, I get a -1 response with
> errno==EINVAL.
There are lots of restrictions to PERF_EVENT_IOC_SET_OUTPUT.
Likely you're violating that it has to be on the same CPU or same task.
-Andi
next prev parent reply other threads:[~2017-04-19 15:46 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-04-19 15:15 perf_event sampling a multithreaded process - ioctl with PERF_EVENT_IOC_SET_OUTPUT fails Daniel John FitzGerald
2017-04-19 15:46 ` Andi Kleen [this message]
2017-04-19 16:37 ` Daniel John FitzGerald
2017-04-19 16:51 ` Daniel John FitzGerald
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