Re: [PATCH] perf/x86: fix Haswell precise store data source encoding

From: Andi Kleen
Date: Thu May 15 2014 - 10:33:08 EST


On Thu, May 15, 2014 at 01:53:37PM +0200, Stephane Eranian wrote:
>
> This patches fixes a bug in precise_store_data_hsw() whereby
> it would set the data source memory level to the wrong value.
>
> As per the the SDM Vol 3b Table 18-41 (Layout of Data Linear
> Address Information in PEBS Record), when status bit 0 is set
> this is a L1 hit, otherwise this is a L1 miss.
>
> This patch encodes the memory level according to the specification.

It's not enough. as I said it needs more fixes.

For most events it should be _NA, _STORE can be only specified
for the explicit _STORE events.

-Andi

>
> Signed-off-by: Stephane Eranian <eranian@xxxxxxxxxx>
>
> diff --git a/arch/x86/kernel/cpu/perf_event_intel_ds.c b/arch/x86/kernel/cpu/perf_event_intel_ds.c
> index ae96cfa..81424f6 100644
> --- a/arch/x86/kernel/cpu/perf_event_intel_ds.c
> +++ b/arch/x86/kernel/cpu/perf_event_intel_ds.c
> @@ -114,9 +114,13 @@ static u64 precise_store_data_hsw(u64 status)
>
> dse.val = 0;
> dse.mem_op = PERF_MEM_OP_STORE;
> - dse.mem_lvl = PERF_MEM_LVL_NA;
> + dse.mem_lvl = PERF_MEM_LVL_L1;
> +
> if (status & 1)
> - dse.mem_lvl = PERF_MEM_LVL_L1;
> + dse.mem_lvl |= PERF_MEM_LVL_HIT;
> + else
> + dse.mem_lvl |= PERF_MEM_LVL_MISS;
> +
> /* Nothing else supported. Sorry. */
> return dse.val;
> }

--
ak@xxxxxxxxxxxxxxx -- Speaking for myself only
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