Systrace conversion loses information about ftrace flags

[ChunelFeng]

as you know, i use v30.0 as default,

when we try to translate perfetto dump file to xxx.strace,
it shows lost some of state.

this state need enable some cfg by my_test.cfg,
or just has no such info?

[LalitMaganti]

When converting to systrace, we try and preserve as much information as we can but the conversion is a lossy process. One of the things which is not preserved is the systrace flags, we just hardcode .....

It might be possible to fix this by reading the flags from the ftrace table and determining what the textural flags are and write it out in the conversion code [1] but I'm not sure if we actually have the information to do this present in the trace at all.

In any case, this is one of those niche cases where contributions are welcome to fix this issue (it's actually a pretty self-contained issue) but given this is the first time this question is asked in 7 years of Perfetto, not a priority for us to fix.

[1] https://cs.android.com/android/platform/superproject/main/+/main:external/perfetto/src/trace_processor/perfetto_sql/intrinsics/functions/to_ftrace.cc;l=700?q=%22writer-%3EAppendLiteral(%5C%22%5D%20....%20%5C%22);%22

[ChunelFeng]

hi, any news about this issue?

[LalitMaganti]

What news are you expecting? As I said, this is not a priority for us to fix. Patches welcome but we're not doing anything on this for the foreseeable future.