> Hi, > also after fixing this issue my bootstrap failes with: > > Permission error mapping pages. > Consider increasing /proc/sys/kernel/perf_event_mlock_kb, > or try again with a smaller value of -m/--mmap_pages. > (current value: 4294967295,0) > Permission error mapping pages. > Consider increasing /proc/sys/kernel/perf_event_mlock_kb, > or try again with a smaller value of -m/--mmap_pages. > (current value: 4294967295,0) > Permission error mapping pages. > Consider increasing /proc/sys/kernel/perf_event_mlock_kb, > or try again with a smaller value of -m/--mmap_pages. > (current value: 4294967295,0) > > this happens on my setup when perf is run multiple times in parallel > and bootstrapping without -j256 indeed continues (but slowly). > Since perf record overwrites the previous perf data, I wonder if this > also implies that we lose the profile info due to race conditions? One extra nit I noticed. We use AUTO_PROFILE = gcc-auto-profile --all -c 10000000
I do not see a reason to also profile kernel (i.e. --all flag). Also the count should probably be a prime so we reduce chance getting an interference with a loop? I wonder if we can rely on perf having resonable defaults these days. For some CPUs we measure cycles in other cases taken branches. For taken branches 10000000 may be bit high? Honza > > Honza
