From: Andi Kleen <ak@linux.intel.com>
To: Greg KH <greg@kroah.com>
Cc: kan.liang@linux.intel.com, peterz@infradead.org,
mingo@redhat.com, linux-kernel@vger.kernel.org,
eranian@google.com, namhyung@kernel.org, acme@kernel.org,
jolsa@redhat.com
Subject: Re: [PATCH 2/7] perf: Create a symlink for a PMU
Date: Fri, 25 Jun 2021 07:22:08 -0700 [thread overview]
Message-ID: <540d8a38-da12-56c8-8306-8d3d61ae1d6b@linux.intel.com> (raw)
In-Reply-To: <YNVneO6exCS4ETRt@kroah.com>
On 6/24/2021 10:19 PM, Greg KH wrote:
> On Thu, Jun 24, 2021 at 10:28:36AM -0700, Andi Kleen wrote:
>>> But a driver does not caer. And if perf does not care, who cares?
>> The users who write scripts that specify the perf events on the perf command
>> line.
> Great, then as you have deemed the device name part of your documented
> api, then keep it stable as that is what you decided to do a long time
> ago when it was created.
The fully supported driver keeps it stable, but the driver in fallback
mode (as in running on a yet unknown system) can't because it doesn't
have enough information. It has to fall back to the numeric identifiers.
Supporting yet unknown systems is a big advantage, missing full kernel
support is the number one reason people can't use uncore monitoring today.
The symlink keeps some degree of compatibility between the two.
Anyways thinking about it if Greg doesn't want symlinks (even though
sysfs already has symlinks elsewhere), maybe we could just create two
devices without symlinks. Kan, do you think that would work?
-Andi
next prev parent reply other threads:[~2021-06-25 14:22 UTC|newest]
Thread overview: 33+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-06-24 1:22 [PATCH 0/7] perf: Add Sapphire Rapids server uncore support kan.liang
2021-06-24 1:22 ` [PATCH 1/7] driver core: Add a way to get to bus devices kset kan.liang
2021-06-24 5:41 ` Greg KH
2021-06-24 1:22 ` [PATCH 2/7] perf: Create a symlink for a PMU kan.liang
2021-06-24 5:48 ` Greg KH
2021-06-24 14:24 ` Andi Kleen
2021-06-24 14:29 ` Greg KH
2021-06-24 15:24 ` Andi Kleen
2021-06-24 15:31 ` Greg KH
2021-06-24 17:07 ` Liang, Kan
2021-06-24 17:35 ` Greg KH
2021-06-24 17:49 ` Andi Kleen
2021-06-25 5:18 ` Greg KH
2021-06-25 5:17 ` Greg KH
2021-06-24 17:28 ` Andi Kleen
2021-06-25 5:19 ` Greg KH
2021-06-25 14:22 ` Andi Kleen [this message]
2021-06-25 14:38 ` Greg KH
2021-06-25 14:49 ` Andi Kleen
2021-06-25 15:03 ` Liang, Kan
2021-06-25 15:44 ` Andi Kleen
2021-06-25 15:57 ` Liang, Kan
2021-06-25 16:18 ` Liang, Kan
2021-06-27 11:02 ` Greg KH
2021-06-27 16:30 ` Andi Kleen
2021-06-28 6:55 ` Greg KH
2021-06-28 15:00 ` Andi Kleen
2021-06-24 1:22 ` [PATCH 3/7] perf/x86/intel/uncore: Create a symlink for an uncore PMU kan.liang
2021-06-24 5:44 ` Greg KH
2021-06-24 1:22 ` [PATCH 4/7] perf/x86/intel/uncore: Add Sapphire Rapids server support kan.liang
2021-06-24 1:22 ` [PATCH 5/7] perf/x86/intel/uncore: Factor out snr_uncore_mmio_map() kan.liang
2021-06-24 1:22 ` [PATCH 6/7] perf/x86/intel/uncore: Support free-running counters on Sapphire Rapids server kan.liang
2021-06-24 1:22 ` [PATCH 7/7] perf/x86/intel/uncore: Fix invalid unit check kan.liang
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