Re: trace-cmd profile is not working

[Steven Rostedt <rostedt@goodmis.org>]

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?

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

Thanks!

-- Steve