Re: [RFC] perf/x86/intel/uncore: pmu->type->single_fixed question
From: Jiri Olsa
Date: Wed Dec 14 2016 - 06:57:30 EST
On Mon, Dec 12, 2016 at 02:49:03PM +0000, Liang, Kan wrote:
> > I really would prefer to move the thing to its own PMU.
> The patch as below creates a new PMU to fix the issue.
> Jirka, could you please try the patch on your machine?
> From 2de8b2eda6b54734e08a608b5fc8c367b94369d3 Mon Sep 17 00:00:00 2001
> From: Kan Liang <kan.liang@xxxxxxxxx>
> Date: Mon, 12 Dec 2016 09:03:35 -0500
> Subject: [PATCH] perf/x86/intel/uncore: fix nonexistent clockticks event for
> client uncore
> The clockticks event can only be used by the first Cbox pmu. Other
> Cboxes don't allow to open clockticks event, eventhough it's announced
> via /sys/../events/..
> For client uncore, there is only one clocktick fixed counter. Current
> kernel code forces that only the first box can access the fixed counter
> in uncore_pmu_event_init. But it doesn't take care of the the
> attr_groups. All the pmus of same type share the same attr_groups. If
> the clockticks event is set for the first box, user can also observe the
> event in other boxes.
> The clocktick fixed counter is a standalone counter. It should be
> removed from the Cbox PMUs. A new type of PMU is added which only
> supports fixed counter events.
> User observable changes with the patch.
> clockticks event is removed from Cbox. It will return unsupported, if
> uncore_cbox_0/clockticks/ is accessed. User may need to change their
> script to use uncore_clock/clockticks/ to instead.
> Signed-off-by: Kan Liang <kan.liang@xxxxxxxxx>
Tested-by: Jiri Olsa <jolsa@xxxxxxxxxx>