linux-kernel - Re: [PATCH 0/3] perf intel-pt: Add PEBS-via-PT side-band

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Date:   Mon, 21 Jun 2021 09:15:10 +0300
From:   Adrian Hunter <adrian.hunter@...el.com>
To:     Peter Zijlstra <peterz@...radead.org>
Cc:     Ingo Molnar <mingo@...hat.com>,
        Arnaldo Carvalho de Melo <acme@...nel.org>,
        Mark Rutland <mark.rutland@....com>,
        Alexander Shishkin <alexander.shishkin@...ux.intel.com>,
        Jiri Olsa <jolsa@...hat.com>, Leo Yan <leo.yan@...aro.org>,
        Kan Liang <kan.liang@...ux.intel.com>, x86@...nel.org,
        linux-perf-users@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH 0/3] perf intel-pt: Add PEBS-via-PT side-band

On 9/06/21 5:20 pm, Adrian Hunter wrote:
> Hi
> 
> PEBS output to Intel Processor Trace was introduced with Atom
> processors based on Tremont.  Currently there is software support
> only for a single PEBS-via-PT event.
> 
> Here is support for multiple PEBS-via-PT events.

Any comments on this patch set?

> 
> The first patch is the kernel change which adds a new event,
> namely PERF_RECORD_AUX_OUTPUT_HW_ID which contains the counter
> index.  That is output when the PEBS-via-PT event is enabled in hardware.
> There is an optimization, to report the index only when it changes
> for the event.  That will work only so long as all PEBS-via-PT
> events are scheduled together, which they are for a recording
> session because they are in a single group.
> 
> Also no attribute bit is used to select the new event, so a new
> kernel is not compatible with older perf tools.  The assumption
> being that PEBS-via-PT is sufficiently esoteric that users will not
> be troubled by this.
> 
> The second patch adds the usual boiler plate to perf tools for
> a new event.
> 
> The third patch adds support for processing the new event by
> perf tool's Intel PT decoder.
> 
> 
> Adrian Hunter (3):
>       perf/x86: Add new event for AUX output counter index
>       perf tools: Add support for PERF_RECORD_AUX_OUTPUT_HW_ID
>       perf intel-pt: Add support for PERF_RECORD_AUX_OUTPUT_HW_ID
> 
>  arch/x86/events/core.c                     |  1 +
>  arch/x86/events/intel/ds.c                 | 16 ++++++
>  include/linux/perf_event.h                 |  2 +
>  include/uapi/linux/perf_event.h            | 15 ++++++
>  kernel/events/core.c                       | 30 +++++++++++
>  tools/include/uapi/linux/perf_event.h      | 15 ++++++
>  tools/lib/perf/include/perf/event.h        |  6 +++
>  tools/perf/Documentation/perf-intel-pt.txt |  7 ++-
>  tools/perf/builtin-inject.c                |  4 +-
>  tools/perf/builtin-record.c                |  2 +-
>  tools/perf/util/event.c                    | 18 +++++++
>  tools/perf/util/event.h                    |  5 ++
>  tools/perf/util/intel-pt.c                 | 85 ++++++++++++++++++++++++++++--
>  tools/perf/util/machine.c                  | 10 ++++
>  tools/perf/util/machine.h                  |  2 +
>  tools/perf/util/session.c                  |  5 ++
>  tools/perf/util/tool.h                     |  1 +
>  17 files changed, 217 insertions(+), 7 deletions(-)
> 
> 
> Regards
> Adrian
>