Re: [PATCH v5 5/5] perf mem: Support mem_lvl_num in c2c command

[Liang, Kan]

On 4/8/2022 3:53 PM, Ali Saidi wrote:
> In addition to summarizing data encoded in mem_lvl also support data
> encoded in mem_lvl_num.
>
> Since other architectures don't seem to populate the mem_lvl_num field
> here there shouldn't be a change in functionality.
>
> Signed-off-by: Ali Saidi <alisaidi@xxxxxxxxxx>
> ---
>   tools/perf/util/mem-events.c | 11 +++++++----
>   1 file changed, 7 insertions(+), 4 deletions(-)
>
> diff --git a/tools/perf/util/mem-events.c b/tools/perf/util/mem-events.c
> index ed0ab838bcc5..e5e405185498 100644
> --- a/tools/perf/util/mem-events.c
> +++ b/tools/perf/util/mem-events.c
> @@ -485,6 +485,7 @@ int c2c_decode_stats(struct c2c_stats *stats, struct mem_info *mi)
>   	u64 daddr  = mi->daddr.addr;
>   	u64 op     = data_src->mem_op;
>   	u64 lvl    = data_src->mem_lvl;
> +	u64 lnum   = data_src->mem_lvl_num;
>   	u64 snoop  = data_src->mem_snoop;
>   	u64 lock   = data_src->mem_lock;
>   	u64 blk    = data_src->mem_blk;
> @@ -527,16 +528,18 @@ do {				\
>   			if (lvl & P(LVL, UNC)) stats->ld_uncache++;
>   			if (lvl & P(LVL, IO))  stats->ld_io++;
>   			if (lvl & P(LVL, LFB)) stats->ld_fbhit++;
> -			if (lvl & P(LVL, L1 )) stats->ld_l1hit++;
> -			if (lvl & P(LVL, L2 )) stats->ld_l2hit++;
> -			if (lvl & P(LVL, L3 )) {
> +			if (lvl & P(LVL, L1) || lnum == P(LVLNUM, L1))
> +				stats->ld_l1hit++;
> +			if (lvl & P(LVL, L2) || lnum == P(LVLNUM, L2))
> +				stats->ld_l2hit++;
> +			if (lvl & P(LVL, L3) || lnum == P(LVLNUM, L3)) {
>   				if (snoop & P(SNOOP, HITM))
>   					HITM_INC(lcl_hitm);
>   				else
>   					stats->ld_llchit++;
>   			}
>   
> -			if (lvl & P(LVL, LOC_RAM)) {
> +			if (lvl & P(LVL, LOC_RAM) || lnum == P(LVLNUM, RAM)) {

I think the PERF_MEM_LVLNUM_RAM only means it's a DRAM.
It doesn't contain the location information. To distinguish the local 
and remote dram, X86 uses PERF_MEM_REMOTE_REMOTE.
Here the remote dram will be mistakenly calculated if you only check the 
PERF_MEM_LVLNUM_RAM.

Actually, it looks like the mem_lvl_num fields supported in this patch 
are also supported by the PERF_MEM_LVL*. Why don't you set both 
PERF_MEM_LVLNUM_* and PERF_MEM_LVL* in your previous patch 4?
Then you can drop this patch.

Thanks,
Kan
>   				stats->lcl_dram++;
>   				if (snoop & P(SNOOP, HIT))
>   					stats->ld_shared++;