Re: [PATCH] perf tools: Exit recording if events have non matchingsample type

From: David Ahern
Date: Thu Sep 29 2011 - 18:55:33 EST




On 09/29/2011 04:05 PM, Arnaldo Carvalho de Melo wrote:
> Em Thu, Sep 29, 2011 at 06:01:08PM +0200, Jiri Olsa escreveu:
>> The event processing relies on all events having the same sample_type.
>>
>> This is being checked when the session is being opened read only.
>> It also needs to be checked when we do record, since events could be
>> read during processing build IDs at the end of the record command.
>>
>> If we process events with different sample_type the processing might
>> skip some events or hang.
>>
>> Following command hangs on my setup:
>> ./perf record -o perf.data -e ext4:ext4_mb_new_group_pa \
>> -e LLC-loads -- date '+%F'
>>
>> because hardware and tracepoint events have different sample type.
>>
>> With the patch applied the record command displays
>> "Non matching sample_type" message and exits.
>
> That is way too cryptic :-\
>
> What is that makes the sample type not match in this case? Can we make
> it match instead?
>
> This is something to be properly fixed by _allowing_ non matching sample
> types, the evsel/evlist abstractions are getting we close but not there
> yet, multiple files in a perf.data/ directory are needed.

>From what I can see sample_type has to be the same for all samples:
https://lkml.org/lkml/2011/8/15/6


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