[llvm-dev] Error with perf2bolt in LLVM BOLT

[Venugopal Raghavan via llvm-dev]

Hi,

I was interested in trying out LLVM BOLT and generated profile data using
Linux perf using the following:

perf record -e cycles:u -o perf.data <command>

This is without the use of LBR so I understand the performance improvements
may not be much but this was more for becoming familiar with BOLT's
commands.

I then run:

perf2bolt -nl -p perf.data -o perf.fdata <binary>

and I get the following:

PERF2BOLT: Starting data aggregation job for perf.data
PERF2BOLT: spawning perf job to read events without LBR
PERF2BOLT: spawning perf job to read mem events
PERF2BOLT: spawning perf job to read process events
PERF2BOLT: spawning perf job to read task events
BOLT-INFO: Target architecture: x86_64
*BOLT-ERROR: input file was processed by BOLT. Cannot re-optimize.*

Not sure why I get the above error. Can someone who has used BOLT help me?

Thanks.

Regards,
Venugopal Raghavan.
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