Currently pprof will print output for all threads if a single thread is not
specified, but this doesn't play well with many output formats (e.g., any of
the dot-based formats). Instead, default to printing just the overall profile
when no specific thread is requested.
This resolves#157.
- Add a --thread N option to select profile for thread N (otherwise, all
threads will be printed)
- The $profile map now has a {threads} element that is a map from thread id to
a profile that has the same format as the {profile} element
- Refactor ReadHeapProfile into smaller components and use them to implement
ReadThreadedHeapProfile
Simplify backtracing to not ignore any frames, and compensate for this
in pprof in order to increase flexibility with respect to function-based
refactoring even in the presence of non-deterministic inlining. Modify
pprof to blacklist all jemalloc allocation entry points including
non-standard ones like mallocx(), and ignore all allocator-internal
frames. Prior to this change, pprof excluded the specifically
blacklisted functions from backtraces, but it left allocator-internal
frames intact.
