From: Anshuman Khandual <khandual@linux.vnet.ibm.com>
To: "Yan, Zheng" <zheng.z.yan@intel.com>
Cc: a.p.zijlstra@chello.nl, mingo@elte.hu, andi@firstfloor.org,
eranian@google.com, jolsa@redhat.com, ming.m.lin@intel.com,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH 2/9] perf: Allow pmu to choose cpu on which to install event
Date: Wed, 09 May 2012 12:08:51 +0530 [thread overview]
Message-ID: <4FAA10FB.1030008@linux.vnet.ibm.com> (raw)
In-Reply-To: <1335924440-11242-3-git-send-email-zheng.z.yan@intel.com>
On Wednesday 02 May 2012 07:37 AM, Yan, Zheng wrote:
> From: "Yan, Zheng" <zheng.z.yan@intel.com>
>
> Allow the pmu->event_init callback to change event->cpu, so pmu can
> choose cpu on which to install event.
>
> Signed-off-by: Zheng Yan <zheng.z.yan@intel.com>
> ---
> kernel/events/core.c | 13 +++++++++----
> 1 files changed, 9 insertions(+), 4 deletions(-)
>
> diff --git a/kernel/events/core.c b/kernel/events/core.c
> index 32cfc76..84911de 100644
> --- a/kernel/events/core.c
> +++ b/kernel/events/core.c
> @@ -6250,6 +6250,8 @@ SYSCALL_DEFINE5(perf_event_open,
> }
> }
>
> + get_online_cpus();
Why this protection against cpu hotplug operation ? Is this because PMU now can change event->cpu
during event initialization (specific to uncore PMU events) or this protection has always been required
for normal on-cpu HW PMU events also and we added it right now ?
next prev parent reply other threads:[~2012-05-09 6:39 UTC|newest]
Thread overview: 38+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-05-02 2:07 [PATCH V3 0/9] perf: Intel uncore pmu counting support Yan, Zheng
2012-05-02 2:07 ` [PATCH 1/9] perf: Export perf_assign_events Yan, Zheng
2012-05-02 2:07 ` [PATCH 2/9] perf: Allow pmu to choose cpu on which to install event Yan, Zheng
2012-05-09 6:38 ` Anshuman Khandual [this message]
2012-05-10 1:09 ` Yan, Zheng
2012-05-10 3:41 ` Anshuman Khandual
2012-05-10 10:56 ` Peter Zijlstra
2012-05-02 2:07 ` [PATCH 3/9] perf: Introduce perf_pmu_migrate_context Yan, Zheng
2012-05-02 2:07 ` [PATCH 4/9] perf: Generic intel uncore support Yan, Zheng
2012-05-03 17:12 ` Peter Zijlstra
2012-05-04 7:33 ` Yan, Zheng
2012-05-04 17:57 ` Peter Zijlstra
2012-05-10 7:34 ` Yan, Zheng
2012-05-10 10:05 ` Peter Zijlstra
2012-05-11 1:54 ` Yan, Zheng
2012-05-03 21:49 ` Peter Zijlstra
2012-05-11 6:31 ` Anshuman Khandual
2012-05-11 6:41 ` Yan, Zheng
2012-05-02 2:07 ` [PATCH 5/9] perf: Add Nehalem and Sandy Bridge " Yan, Zheng
2012-05-03 21:04 ` Peter Zijlstra
2012-05-04 5:47 ` Yan, Zheng
2012-05-03 21:04 ` Peter Zijlstra
2012-05-02 2:07 ` [PATCH 6/9] perf: Generic pci uncore device support Yan, Zheng
2012-05-03 21:37 ` Peter Zijlstra
2012-05-03 21:39 ` Peter Zijlstra
2012-05-03 21:46 ` Peter Zijlstra
2012-05-04 6:07 ` Yan, Zheng
2012-05-02 2:07 ` [PATCH 7/9] perf: Add Sandy Bridge-EP uncore support Yan, Zheng
2012-05-03 21:12 ` Peter Zijlstra
2012-05-02 2:07 ` [PATCH 8/9] perf tool: Make the event parser reentrantable Yan, Zheng
2012-05-02 2:07 ` [PATCH 9/9] perf tool: Add pmu event alias support Yan, Zheng
2012-05-03 10:56 ` Jiri Olsa
2012-05-03 11:24 ` Peter Zijlstra
2012-05-03 20:05 ` Jiri Olsa
2012-05-04 12:32 ` Yan, Zheng
2012-05-07 8:34 ` Yan, Zheng
2012-05-10 9:52 ` Jiri Olsa
2012-05-07 17:14 ` Peter Zijlstra
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