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SubjectRe: [PATCH 8/8][v4] powerpc/perf: Export Power7 memory hierarchy info to user space.
On 09/14/2013 06:19 AM, Sukadev Bhattiprolu wrote:
> On Power7, the DCACHE_SRC field in MMCRA register identifies the memory
> hierarchy level (eg: L2, L3 etc) from which a data-cache miss for a
> marked instruction was satisfied.
>
> Use the 'perf_mem_data_src' object to export this hierarchy level to user
> space. Some memory hierarchy levels in Power7 don't map into the arch-neutral
> levels. However, since newer generation of the processor (i.e. Power8) uses
> fewer levels than in Power7, we don't really need to define new hierarchy
> levels just for Power7.
>
> We instead, map as many levels as possible and approximate the rest. See
> comments near dcache-src_map[] in the patch.
>
> Usage:
>
> perf record -d -e 'cpu/PM_MRK_GRP_CMPL/' <application>
> perf report -n --mem-mode --sort=mem,sym,dso,symbol_daddr,dso_daddr"
>
> For samples involving load/store instructions, the memory
> hierarchy level is shown as "L1 hit", "Remote RAM hit" etc.
> # or
>
> perf record --data <application>
> perf report -D
>
> Sample records contain a 'data_src' field which encodes the
> memory hierarchy level: Eg: data_src 0x442 indicates
> MEM_OP_LOAD, MEM_LVL_HIT, MEM_LVL_L2 (i.e load hit L2).

Successfully built and boot tested this entire patchset both on a P7 and P8 system.
Running some sample tests with ebizzy micro benchmark. Till now got only 0x142 and
0x0 values for data_src object for the sample records. Will experiment around bit
more on P7 and P8 systems and post the results.

Regards
Anshuman



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