Re: [PATCH 1/2] perf/arm-cmn: Fix PMU instance naming

On 2021-01-28 20:14, Will Deacon wrote:

On Thu, Jan 28, 2021 at 01:12:43PM +0000, Robin Murphy wrote:

quoted

Although it's neat to avoid the suffix for the typical case of a
single PMU, it means systems with multiple CMN instances end up with
inconsistent naming. I think it also breaks perf tool's "uncore alias"
logic if the common instance prefix is also the full name of one.

Avoid any surprises by not trying to be clever and simply numbering
every instance, even when it might technically prove redundant.

Fixes: 0ba64770a2f2 ("perf: Add Arm CMN-600 PMU driver")
Signed-off-by: Robin Murphy <robin.murphy@arm.com>
---
  Documentation/admin-guide/perf/arm-cmn.rst |  2 +-
  drivers/perf/arm-cmn.c                     | 13 ++++---------
  2 files changed, 5 insertions(+), 10 deletions(-)

Hmm, so usually I'd push-back on changes like this because it's a
user-visible change, however in this case we're talking about a pretty
niche PMU and a relatively new driver so I think we should proceed. However,
if anybody complains then we'll need to support them in one way or another.

Yeah, I'm kicking myself for not remembering about the aliasing thing 
from the start - it came up tangentially from conversation with some 
interested users the other day - so hopefully the practicality will 
outweigh any possible early-adopter inconvenience.

Thanks,
Robin.

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