No way to specify PERF_FLAG_FD_OUTPUT (?) about perf HOT 6 CLOSED

The man page for PERF_FLAG_FD_OUTPUT says "broken since Linux 2.6.35". My memory is a little hazy, but I believe you're meant to use PERF_EVENT_IOC_SET_OUTPUT, which is (*Event).SetOutput in this API.

from perf.

If it might require a change to the signature of Open, it seems worth fixing before trying to publish this in golang.org/x/...

from perf.

Please let me know if that works as expected. I see now there is a big comment on SetOutput, and I don't remember all the details.

from perf.

I'm yet to succeed at getting this to work but I've only had limited time to try so far. It seems to make sense to me.

However, what if the kernel introduces a new useful flag in the future?

How could they be specified then? Given current use cases it seems all good, though, so I'm happy to close this.

from perf.

@pwaller were you able to successfully achieve your goal? I also would like to reduce the number of ring buffers I need to consume. Your reason is better than mine (ordering guaranteed by the kernel).

But then you also mention you were unable to make it work. It is my understanding that this functionality (setting the output) is used by BPF so it is not considered broken.

from perf.

I don't think I got to the end of my journey of trying to get BPF working as I wanted to. Please file another issue if you have another legitimate use case for it. I'm going to close this one for now.

from perf.