linux-kernel - Re: [PATCH] perf record: enable multiplexing scaling via -R

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Message-ID: <20170828204114.GR2482@two.firstfloor.org>
Date:   Mon, 28 Aug 2017 13:41:14 -0700
From:   Andi Kleen <andi@...stfloor.org>
To:     Stephane Eranian <eranian@...gle.com>
Cc:     Jiri Olsa <jolsa@...hat.com>, Andi Kleen <andi@...stfloor.org>,
        LKML <linux-kernel@...r.kernel.org>,
        Arnaldo Carvalho de Melo <acme@...hat.com>,
        Peter Zijlstra <peterz@...radead.org>,
        "mingo@...e.hu" <mingo@...e.hu>, "Liang, Kan" <kan.liang@...el.com>
Subject: Re: [PATCH] perf record: enable multiplexing scaling via -R

> So I think we are good to go. to capture multiplexing scaling factor
> when sampling simply use the S
> modifier.
> But to my surprise, newer kernels are not happy with the cmdline:
> $ perf record -e cycles:S  noploop 1
> Error:
> The sys_perf_event_open() syscall returned with 22 (Invalid argument)
> for event (cycles:Su).
> /bin/dmesg may provide additional information.
> No CONFIG_PERF_EVENTS=y kernel support configured?

Likely due to 

ba5213ae6b88 perf/core: Correct event creation with PERF_FORMAT_GROUP

It's not supported with inherited events.

-Andi