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

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Message-ID: <fd5a6b16-9297-5b11-53d1-4ff3d5be1ddd@os.amperecomputing.com>
Date:   Tue, 28 Mar 2023 09:16:23 -0700
From:   Yang Shi <yang@...amperecomputing.com>
To:     James Clark <james.clark@....com>, 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
Subject: Re: [BUG] perf: No samples found when using kcore + coresight



On 3/28/23 1:59 AM, James Clark wrote:
>
> 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.

Hi James,

Thank you for the update.

>
> 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