Re: [PATCH v8 2/5] perf tools: sync addition of PERF_MEM_SNOOPX_PEER

Arnaldo Carvalho de Melo
2022-05-10T16:29:32Z

Em Wed, May 04, 2022 at 06:48:47PM +0000, Ali Saidi escreveu:
> 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>

Was this already merged on the ARM kernel tree?

- Arnaldo

> ---
> tools/include/uapi/linux/perf_event.h | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/tools/include/uapi/linux/perf_event.h b/tools/include/uapi/linux/perf_event.h
> index d37629dbad72..7b88bfd097dc 100644
> --- a/tools/include/uapi/linux/perf_event.h
> +++ b/tools/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 */
> --
> 2.32.0

--

- Arnaldo