Re: trace-cmd profile is not working

[Jerome Marchand <jmarchan@redhat.com>]

On 12/05/2021 15:55, Steven Rostedt wrote:
> On Wed, 12 May 2021 15:51:52 +0200
> Jerome Marchand <jmarchan@redhat.com> wrote:
> 
>> Hi,
>>
>> Streams, and thus trace-cmd profile, are not working. A simple
>> "trace-cmd profile ls" command exit with the following message
>> "Creating stream for 0". I've been looking at it and the issue is that
>> tracecmd_read_headers() tries to read the cmdlines, cpus and options
>> sections that have not been written to the temporary file when called
>> from trace_stream_init().
>>
>> AFAICT, it is caused by the two following patches:
>>
>> commit 1eea02a4 ("trace-cmd: Write saved cmdlines in the trace file at
>> the end of the trace.") which moved the writing of cmdlines from
>> create_file_fd() to tracecmd_create_file_latency() and
>> tracecmd_append_cpu_data()
>>
>> commit 5d4d7ec3 ("trace-cmd: Move reading of trace.dat options to
>> tracecmd_read_headers()") which moved the reading of options and cpu
>> datas to tracecmd_read_headers().
>>
> 
> Thanks for the report. I'm not surprised, profiling and streams have not
> been given the love they deserve (been focusing on host/guest tracing
> recently).
> 
> Can you fill out a bug report on bugzilla?

Sure thing:
https://bugzilla.kernel.org/show_bug.cgi?id=213045

Jerome

> 
>    https://bugzilla.kernel.org/buglist.cgi?component=Trace-cmd%2FKernelshark&list_id=1090417&product=Tools&resolution=---
> 
> Thanks!
> 
> -- Steve
>