Andi Kleen <a...@firstfloor.org> writes: > From: Andi Kleen <a...@linux.intel.com> > > With high -j parallelism the autofdo tests can randomly fail. > autofdo uses Linux perf to record profiling data. > Linux perf uses a locked perf buffer. By default it has > around 516k buffer per uid (/proc/sys/kernel/perf_event_mlock_kb). > > An individual perf record tries to grab the full 516k, > which makes parallel perf record fail. > > This patch limits the perf buffer for individual perf record to 8k. > With the default settings this allows a parallelism of the test > cases of 16, which is hopefully good enough
So for -jN > 16 it would silently fail again? I think we should warn when the -jN is sufficiently large such that tests will randomly fail, and perhaps suggest workarounds with ulimit/etc. Aldy
