Thread Name Truncated in Perfetto Trace #960
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Hello Perfetto Team, I am encountering an issue with thread names being truncated in Perfetto traces. Specifically, I have a thread named Could you provide guidance on how to display the full thread name in the Perfetto trace output?
Thank you for your assistance! Best regards, Kevin. |
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Replies: 1 comment 7 replies
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The 16 character limitation is limitation of the underlying ftrace data source which the kernel provides for tracing. It is not a limitation of Perfetto itself If full names are important to you, you can turn on the record_thread_names option in the process stats (https://perfetto.dev/docs/reference/trace-config-proto#ProcessStatsConfig) data source which will make us scrape /proc to get the full names. Note that this is somewhat expensive which is why we do not turn it on by default. |
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I have already tried keeping sched_switch enabled, but still can't display the full thread names. If you have the correct command to capture the trace with full thread name , could you please send it to me? |
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Unless the thread is short lived, enabling |
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If that's not working, I'm not sure what's wrong as I cannot repro this issue: we use this option occasionally and it works fine for us. |
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Thank you very much for your detailed response. I will try some other methods. |
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Actually I investigated this more now I got some time: I was misremembering when I said above. There is no option to collect full thread names. This is not a Perfetto problem, this is a limitation of the kernel itself. e.g. see https://stackoverflow.com/questions/5026531/thread-name-longer-than-15-chars I'm not aware of any API in Linux which actually would give the full names, if you find one, let us know and we can add support for this. |
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The 16 character limitation is limitation of the underlying ftrace data source which the kernel provides for tracing. It is not a limitation of Perfetto itself
If full names are important to you, you can turn on the record_thread_names option in the process stats (https://perfetto.dev/docs/reference/trace-config-proto#ProcessStatsConfig) data source which will make us scrape /proc to get the full names. Note that this is somewhat expensive which is why we do not turn it on by default.