From: Peter Zijlstra <peterz@infradead.org>
To: Saravana Kannan <skannan@codeaurora.org>
Cc: mark.rutland@arm.com, Ingo Molnar <mingo@redhat.com>,
Arnaldo Carvalho de Melo <acme@kernel.org>,
Alexander Shishkin <alexander.shishkin@linux.intel.com>,
Jiri Olsa <jolsa@redhat.com>, Namhyung Kim <namhyung@kernel.org>,
avilaj@codeaurora.org, linux-arm-kernel@lists.infradead.org,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH v1 1/2] perf/core: Add API to look up PMU type by name
Date: Sat, 24 Feb 2018 09:08:09 +0100 [thread overview]
Message-ID: <20180224080809.GA25201@hirez.programming.kicks-ass.net> (raw)
In-Reply-To: <1519431578-11995-1-git-send-email-skannan@codeaurora.org>
On Fri, Feb 23, 2018 at 04:19:37PM -0800, Saravana Kannan wrote:
> When the event numbers registered by multiple PMUs overlap, the
> attr->type value passed to perf_event_create_kernel_counter() is used
> to determine which PMU to use to create a perf_event.
>
> However, when the PMU in question is not a standard PMU (defined in
> perf_type_id), there is no way for a kernel client to look up the PMU
> type for the PMU of interest and set the attr->type appropriately.
>
> So, add an API to look up the PMU type by name. That way, the kernel
> APIs can function in a fashion similar to the user space interface.
>
> Signed-off-by: Saravana Kannan <skannan@codeaurora.org>
> ---
> kernel/events/core.c | 23 +++++++++++++++++++++++
> 1 file changed, 23 insertions(+)
>
> diff --git a/kernel/events/core.c b/kernel/events/core.c
> index 96db9ae..5d3df58 100644
> --- a/kernel/events/core.c
> +++ b/kernel/events/core.c
> @@ -10310,6 +10310,29 @@ static int perf_event_set_clock(struct perf_event *event, clockid_t clk_id)
> return err;
> }
>
> +int perf_find_pmu_type_by_name(const char *name)
> +{
> + struct pmu *pmu;
> + int ret = -1;
> +
> + mutex_lock(&pmus_lock);
> +
> + list_for_each_entry(pmu, &pmus, entry) {
> + if (!pmu->name || pmu->type < 0)
> + continue;
> +
> + if (!strcmp(name, pmu->name)) {
> + ret = pmu->type;
> + goto out;
> + }
> + }
> +
> +out:
> + mutex_unlock(&pmus_lock);
> +
> + return ret;
> +}
Not without an in-tree user.
prev parent reply other threads:[~2018-02-24 8:08 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-02-24 0:19 [PATCH v1 1/2] perf/core: Add API to look up PMU type by name Saravana Kannan
2018-02-24 0:19 ` [PATCH v1 2/2] perf/core: Add support for PMUs that can be read from any CPU Saravana Kannan
2018-02-24 0:56 ` Saravana Kannan
2018-02-24 8:41 ` Peter Zijlstra
2018-02-27 1:53 ` skannan
2018-02-27 11:52 ` Mark Rutland
2018-03-03 15:41 ` Peter Zijlstra
2018-03-07 16:39 ` Jeremy Linton
2018-02-25 14:38 ` Mark Rutland
2018-02-27 2:11 ` skannan
2018-02-27 11:43 ` Mark Rutland
2018-02-27 23:15 ` skannan
2018-02-24 8:08 ` Peter Zijlstra [this message]
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