[0/3] arm64: perf: add support for Cortex-A55/A75/A76

Message

Jisheng Zhang June 19, 2020, 10:44 a.m. UTC

The Cortex-A55/A75/A76 use some implementation defined perf events.
Add the support.

Jisheng Zhang (3):
  arm64: perf: add support for Cortex-A55
  arm64: perf: add support for Cortex-A75
  arm64: perf: add support for Cortex-A76

 arch/arm64/kernel/perf_event.c | 49 +++++++++++++++++++++++++++++++---
 1 file changed, 45 insertions(+), 4 deletions(-)

Comments

Will Deacon July 3, 2020, 12:33 p.m. UTC | #1

On Fri, Jun 19, 2020 at 06:44:37PM +0800, Jisheng Zhang wrote:
> The Cortex-A55/A75/A76 use some implementation defined perf events.
> Add the support.
> 
> Jisheng Zhang (3):
>   arm64: perf: add support for Cortex-A55
>   arm64: perf: add support for Cortex-A75
>   arm64: perf: add support for Cortex-A76
> 
>  arch/arm64/kernel/perf_event.c | 49 +++++++++++++++++++++++++++++++---
>  1 file changed, 45 insertions(+), 4 deletions(-)

Do we really need this? I'd prefer for this stuff to live in userspace
now that the perf tool has supported JSON event descriptions for a while,
and the in-kernel driver advertises the architected events advertised
by PMCEID*.

Will

Jisheng Zhang July 6, 2020, 8:04 a.m. UTC | #2

Hi Will,

On Fri, 3 Jul 2020 13:33:47 +0100 Will Deacon wrote:

> 
> 
> On Fri, Jun 19, 2020 at 06:44:37PM +0800, Jisheng Zhang wrote:
> > The Cortex-A55/A75/A76 use some implementation defined perf events.
> > Add the support.
> >
> > Jisheng Zhang (3):
> >   arm64: perf: add support for Cortex-A55
> >   arm64: perf: add support for Cortex-A75
> >   arm64: perf: add support for Cortex-A76
> >
> >  arch/arm64/kernel/perf_event.c | 49 +++++++++++++++++++++++++++++++---
> >  1 file changed, 45 insertions(+), 4 deletions(-)  
> 
> Do we really need this? I'd prefer for this stuff to live in userspace

IMHO, this stuff is to add a relationship between linux standard
HW events and ARM PMU events, take CA55 for example:

w/o the stuff, perf -e PREFETCH_LINEFILL

w/ the stuff, perf -e L1-dcache-prefetch-misses

But indeed, we also need to add json descriptions in perf tool, I'll submit
patches.

Thanks

> now that the perf tool has supported JSON event descriptions for a while,
> and the in-kernel driver advertises the architected events advertised
> by PMCEID*.
> 
> Will