diff mbox series

[v8,1/5] perf: Add SNOOP_PEER flag to perf mem data struct

Message ID 20220504184850.24986-2-alisaidi@amazon.com (mailing list archive)
State New, archived
Headers show
Series perf: arm-spe: Decode SPE source and use for perf c2c | expand

Commit Message

Ali Saidi May 4, 2022, 6:48 p.m. UTC 
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>
---
 include/uapi/linux/perf_event.h | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

Comments

kajoljain May 11, 2022, 5:41 a.m. UTC | #1 
On 5/5/22 00:18, Ali Saidi wrote:
> 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>
> ---
>  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 */

Patch looks good to me.

Reviewed-By: Kajol Jain<kjain@linux.ibm.com>

Thanks,
Kajol Jain
diff mbox series

Patch

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 */