linux-kernel - Re: [PATCH 2/2] perf arm-spe: Parse more SPE fields and store source

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Date:   Sun, 27 Feb 2022 21:54:44 +0800
From:   Leo Yan <leo.yan@...aro.org>
To:     Ali Saidi <alisaidi@...zon.com>
Cc:     german.gomez@....com, acme@...nel.org,
        alexander.shishkin@...ux.intel.com, andrew.kilroy@....com,
        benh@...nel.crashing.org, james.clark@....com,
        john.garry@...wei.com, jolsa@...hat.com,
        linux-arm-kernel@...ts.infradead.org, linux-kernel@...r.kernel.org,
        linux-perf-users@...r.kernel.org, mark.rutland@....com,
        mathieu.poirier@...aro.org, mingo@...hat.com, namhyung@...nel.org,
        peterz@...radead.org, will@...nel.org
Subject: Re: [PATCH 2/2] perf arm-spe: Parse more SPE fields and store source

On Tue, Feb 22, 2022 at 07:29:43PM +0000, Ali Saidi wrote:

[...]

> >So I am just wandering if we can set the field
> >sample::data_src::mem_lock for atomic operations, like:
> >
> >    data_src.mem_op   = PERF_MEM_OP_LOAD;
> >    data_src.mem_lock = PERF_MEM_LOCK_ATOMIC;
> >
> >The field "mem_lock" is only two bits, we can consider to extend the
> >structure with an extra filed "mem_lock_ext" if it cannot meet our
> >requirement.
> 
> These are for the LOCK instruction on x86. I don't know that we want to
> overload the meaning here. Minimally there is value in differentiating
> exclusives vs atomics.

Good point.  Can we consider to add new filed data_src.atomic with
below types?

    PERF_MEM_ATOMIC_INST  -> Atomic operations
    PERF_MEM_ATOMIC_EXCL  -> Load-Exclusive/Store-Exclusive
    PERF_MEM_ATOMIC_ACQUIRE_RELEASE  ->Load-Acquire/Store-Release

Thanks,
Leo