[lkml]   [2018]   [May]   [4]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
Messages in this thread
SubjectRe: [RFC PATCH] MIPS: Oprofile: Drop support
Hi Robert,

On 04/05/18 10:30, Robert Richter wrote:
> On 24.04.18 14:15:58, Matt Redfearn wrote:
>> On 24/04/18 14:05, James Hogan wrote:
>>> On Tue, Apr 24, 2018 at 01:55:54PM +0100, Matt Redfearn wrote:
>>>> Since it appears that MIPS oprofile support is currently broken, core
>>>> oprofile is not getting many updates and not as many architectures
>>>> implement support for it compared to perf, remove the MIPS support.
>>> That sounds reasonable to me. Any idea how long its been broken?
>> Sorry, not yet. I haven't yet looked into where/how it's broken that would
>> narrow that down...
> oprofile moved to perf syscall as kernel i/f with version 1.0.0. The

OK interesting. I guess this was the point at which MIPS' current
Kconfig rule which only allows building oprofile or perf into a kernel
broke oprofile userspace.

> opcontrol script that was using the oprofile kernel i/f was removed:
> Thus, cpus that do not support the perf syscall are no longer
> supported by 1.x releases.
> For those remainings there is still version 0.9.x available (tagged
> I am undecided whether removing oprofile kernel i/f falls under the
> rule of "never break user space" here. Strictly seen, yes it breaks
> those remainings. So if the perf syscall is not available as an
> alternative, the oprofile kernel support shouldn't be removed.

perf is available for MIPS and supports many more CPU types than
oprofile. oprofile userspace seemingly has been broken since 1.0.0 -
removing oprofile support from the MIPS kernel would not break it more
thatn it already is, but of course it would be better to fix it - if it
is still useful and people still use it. That is the question that I was
looking for answers for with this RFC - whether to spend the time &
effort to fix oprofile, or if it can be removed since everyone uses perf.


> -Robert

 \ /
  Last update: 2018-05-04 11:55    [W:0.069 / U:2.620 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site