Re: [PATCH v5 01/17] perf: Add SNOOP_PEER flag to perf mem data struct

Arnaldo Carvalho de Melo
2022-07-20T18:46:58Z

Em Wed, Jul 20, 2022 at 03:45:51PM -0300, Arnaldo Carvalho de Melo escreveu:
> Em Sat, Jun 04, 2022 at 12:28:04PM +0800, Leo Yan escreveu:
> > From: Ali Saidi <alisaidi@amazon.com>
> >
> > Add a flag to the perf mem data struct to signal that a request caused a
> > cache-to-cache transfer of a line from a peer of the requestor and
> > wasn't sourced from a lower cache level. The line being moved from one
> > peer cache to another has latency and performance implications. On Arm64
> > Neoverse systems the data source can indicate a cache-to-cache transfer
> > but not if the line is dirty or clean, so instead of overloading HITM
> > define a new flag that indicates this type of transfer.
> >
> > Signed-off-by: Ali Saidi <alisaidi@amazon.com>
> > Reviewed-by: Leo Yan <leo.yan@linaro.org>
> > Reviewed-by: Kajol Jain<kjain@linux.ibm.com>
>
> Hey, any knews about this going upstream? PeterZ?

Just took a look and it isn't in tip/master.

- Arnaldo

> > ---
> > include/uapi/linux/perf_event.h | 2 +-
> > 1 file changed, 1 insertion(+), 1 deletion(-)
> >
> > diff --git a/include/uapi/linux/perf_event.h b/include/uapi/linux/perf_event.h
> > index d37629dbad72..7b88bfd097dc 100644
> > --- a/include/uapi/linux/perf_event.h
> > +++ b/include/uapi/linux/perf_event.h
> > @@ -1310,7 +1310,7 @@ union perf_mem_data_src {
> > #define PERF_MEM_SNOOP_SHIFT 19
> >
> > #define PERF_MEM_SNOOPX_FWD 0x01 /* forward */
> > -/* 1 free */
> > +#define PERF_MEM_SNOOPX_PEER 0x02 /* xfer from peer */
> > #define PERF_MEM_SNOOPX_SHIFT 38
> >
> > /* locked instruction */
> > --
> > 2.25.1
>
> --
>
> - Arnaldo

--

- Arnaldo