On Fri, Jun 9, 2023 at 3:28 AM Gregory Smith <gregsmithpg...@gmail.com> wrote: > On Thu, Jun 8, 2023 at 9:21 PM Andres Freund <and...@anarazel.de> wrote: >> >> You might need to add --no-children to the perf report invocation, otherwise >> it'll show you the call graph inverted. > > > My problem was not writing kernel symbols out, I was only getting addresses > for some reason. This worked: > > sudo perf record -g --call-graph dwarf -d --phys-data -a sleep 1 > perf report --stdio
Do you know why using phys-data would have solved the problem in your particular setup? I find figuring out what perf options I need mystifying. I end up trying random things from https://wiki.postgresql.org/wiki/Profiling_with_perf, the perf man page, and https://www.brendangregg.com/perf.html The pg wiki page actually has a lot of detail. If you think your particular problem is something others would encounter, it could be good to add it there. FWIW, I think it is helpful to have hackers threads like this where people work through unexplained performance results with others in the community. - Melanie
