[Intel-gfx] [PATCH] drm/i915/pmu: Do not use colon characters in PMU names

[Chris Wilson]

Quoting Tvrtko Ursulin (2020-01-10 11:27:55)
> 
> On 10/01/2020 11:21, Chris Wilson wrote:
> > Quoting Tvrtko Ursulin (2020-01-10 11:11:26)
> >> From: Tvrtko Ursulin <tvrtko.ursulin at intel.com>
> >>
> >> We use PCI device path in the registered PMU name in order to distinguish
> >> between multiple GPUs. But since tools/perf reserves a special meaning to
> >> the colon character we need to transliterate them to something else. We
> >> choose a dash.
> >>
> >> Signed-off-by: Tvrtko Ursulin <tvrtko.ursulin at intel.com>
> >> Reported-by: Dmitry Rogozhkin <dmitry.v.rogozhkin at intel.com>
> >> Fixes: 05488673a4d4 ("drm/i915/pmu: Support multiple GPUs")
> >> Cc: Chris Wilson <chris at chris-wilson.co.uk>
> >> Cc: Michal Wajdeczko <michal.wajdeczko at intel.com>
> >> Cc: Andi Kleen <ak at linux.intel.com>
> >> ---
> >>   drivers/gpu/drm/i915/i915_pmu.c | 14 ++++++++++++--
> >>   1 file changed, 12 insertions(+), 2 deletions(-)
> >>
> >> diff --git a/drivers/gpu/drm/i915/i915_pmu.c b/drivers/gpu/drm/i915/i915_pmu.c
> >> index f3ef6700a5f2..ecbd0e1f1a90 100644
> >> --- a/drivers/gpu/drm/i915/i915_pmu.c
> >> +++ b/drivers/gpu/drm/i915/i915_pmu.c
> >> @@ -1117,12 +1117,22 @@ void i915_pmu_register(struct drm_i915_private *i915)
> >>          hrtimer_init(&pmu->timer, CLOCK_MONOTONIC, HRTIMER_MODE_REL);
> >>          pmu->timer.function = i915_sample;
> >>   
> >> -       if (!is_igp(i915))
> >> +       if (!is_igp(i915)) {
> >>                  pmu->name = kasprintf(GFP_KERNEL,
> >>                                        "i915-%s",
> >>                                        dev_name(i915->drm.dev));
> >> -       else
> >> +               if (pmu->name) {
> > 
> > /* tools/perf reserves colons as special. */
> > strreplace(pmu->name, ':', '-');
> 
> I didn't know this exists, thanks.
> 
> > I worry because the err_idx pointed to the '-'. We may have to use _
> 
> What is err_idx? But yes.. it would had served me well to test before 
> sending. :) I just find identifiers with a mix of underscores and dashes 
> so visually unappealing. :(

event syntax error: 'i915-0000:00:02.0/bcs0-busy/'
                         \___ parser error

The parser sets err_idx on the character it failed at, and the error
message includes it. So unless we lost whitespace in all the cutting and
pasting, that says it barfed at '-'
-Chris