cmd/pprof: can't specify pprof symbolz endpoint

[anacrolix]

There's no option with go tool pprof to specify the endpoint for the symbols. The current method to derive it from the profile path isn't very flexible, such as when the debug/pprof endpoints are wrapped into a deeper path, for example /some/wrapping/path/debug/pprof/. In this case, pprof determines that the symbols will be at /symbolz, when in fact they should be at /some/wrapping/path/debug/pprof/symbol.

[ianlancetaylor]

CC @matloob @rahulchaudhry

[hyangah]

@anacrolix Given that your PR in google/pprof was merged, is it sufficient if the vendor'ed pprof source is updated? If not, please file an issue to google/pprof.

https://golang.org/cl/75870 update the vendored pprof source recently and should include the PR.

BTW, in what case you will need symbol lookup? My understanding is that go runtime pprof outputs already include symbol info, so pprof would not require extra symbol lookups in most cases. Otherwise, something is not working as intended.

[anacrolix]

It does appear the fixes were merged in aec345d.

Some of the pprof endpoints seem to require the symbols endpoint too. I don't know why this is the case, it appears to be some kind of optimization.