linux-kernel - Re: [BUG] perf: No samples found when using kcore + coresight

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Message-ID: <5a120a90-0b95-cfd0-beff-e9228a9d394b@arm.com>
Date:   Tue, 28 Mar 2023 09:59:25 +0100
From:   James Clark <james.clark@....com>
To:     Yang Shi <shy828301@...il.com>, Leo Yan <leo.yan@...aro.org>
Cc:     linux-perf-users@...r.kernel.org,
        LAK <linux-arm-kernel@...ts.infradead.org>,
        coresight@...ts.linaro.org,
        Linux Kernel Mailing List <linux-kernel@...r.kernel.org>,
        mathieu.poirier@...aro.org, adrian.hunter@...el.com,
        Jiri Olsa <jolsa@...nel.org>, acme@...hat.com,
        mike.leach@...aro.org, Will Deacon <will@...nel.org>,
        suzuki.poulose@....com, yang@...amperecomputing.com
Subject: Re: [BUG] perf: No samples found when using kcore + coresight



On 28/03/2023 01:53, Yang Shi wrote:
> Hi Leo,
> 
> Just follow up on this one. Any update?
> 
Hi Yang,

Sorry no update on this yet from me. I was just finishing off
"coresight: Fix CTI module refcount leak by making it a helper device"
which I hope to post in the next day or two and then I will start on this.

James

> Thanks,
> Yang
> 
> On Mon, Mar 13, 2023 at 5:36 PM Leo Yan <leo.yan@...aro.org> wrote:
>>
>> On Mon, Mar 13, 2023 at 11:15:44AM -0700, Yang Shi wrote:
>>
>> [...]
>>
>>>> Just a quick summary, here we have two issues:
>>>>
>>>> - With command:
>>>>   perf record -e cs_etm/@..._etf63/k --kcore --per-thread \
>>>>   -- taskset --cpu-list 1 uname",
>>>>
>>>>   perf doesn't enable "text poke" attribution.
>>>
>>> No, it enables "text poke" and perf fails to decode coresight trace
>>> data too. It doesn't matter whether "--kcore" is after or before "-e
>>> cs/etm/@..._etf63/k".
>>
>> Understand now.  Thanks for correction, if so we can ignore this one.
>>
>> Leo