These didn't help unfortunately. But I ended up finding Not able to see the profiling results properly for a profile generated from gperftools on mac OS High sierra · Issue #324 · google/pprof · GitHub and from there might have figured some things out.
First, I installed the Go version of pprof with go get and then ran it on my profile (with a lot of trial an error) like this:
$ PPROF_BINARY_PATH=$(pwd)/target/debug /tmp/gopath/bin/pprof /tmp/prof
Local symbolization failed for sandboxfs: error reading Mach-O file /Users/jmmv/os/sandboxfs/./target/debug/sandboxfs: could not identify base for /Users/jmmv/os/sandboxfs/./target/debug/sandboxfs: __TEXT segment address (0x100000000) > mapping start address (0x686e000)
Some binary filenames not available. Symbolization may be incomplete.
Try setting PPROF_BINARY_PATH to the search path for local binaries.
File: libc++.1.dylib
Type: cpu
The error this prints is interesting. So then I went and deleted the last line from the profile (the one that shows a base address lower than the text segment) and ran it again:
PPROF_BINARY_PATH=$(pwd)/target/debug /tmp/gopath/bin/pprof /tmp/prof
Some binary filenames not available. Symbolization may be incomplete.
Try setting PPROF_BINARY_PATH to the search path for local binaries.
File: libc++.1.dylib
Type: cpu
Entering interactive mode (type "help" for commands, "o" for options)
(pprof) text
Showing nodes accounting for 1420ms, 94.04% of 1510ms total
Showing top 10 nodes out of 180
flat flat% sum% cum cum%
370ms 24.50% 24.50% 370ms 24.50% _lstat64
360ms 23.84% 48.34% 360ms 23.84% _writev
260ms 17.22% 65.56% 260ms 17.22% _read
140ms 9.27% 74.83% 140ms 9.27% __platform_memcmp
60ms 3.97% 78.81% 60ms 3.97% ___getdirentries64
60ms 3.97% 82.78% 60ms 3.97% __platform_memmove$VARIANT$Nehalem
50ms 3.31% 86.09% 50ms 3.31% _je_rallocx
40ms 2.65% 88.74% 40ms 2.65% ___mmap
40ms 2.65% 91.39% 40ms 2.65% __platform_memset$VARIANT$Ivybridge
40ms 2.65% 94.04% 40ms 2.65% _fstat64
which now shows symbols and the profile seems to be good.
Still no idea why the regular pprof may not work and why I have to manually edit the profile. Will try on Linux later to see if things work out of the box.