On Mon, Oct 14, 2019 at 11:11:36AM -0300, Arnaldo Carvalho de Melo wrote: > Em Fri, Oct 11, 2019 at 05:19:42PM +0800, Leo Yan escreveu: > > When execute task exit testing case, Perf tool stucks in this case and > > doesn't return back on Arm64 Juno board. > > > > After dig into this issue, since Juno board has Arm's big.LITTLE CPUs, > > thus the PMUs are not compatible between the big CPUs and little CPUs. > > This leads to PMU event cannot be enabled properly when the traced task > > is migrated from one variant's CPU to another variant. Finally, the > > test case runs into infinite loop for cannot read out any event data > > after return from polling. > > > > Eventually, we need to work out formal solution to allow PMU events can > > be freely migrated from one CPU variant to another, but this is a > > difficult task and a different topic. This patch tries to fix the Perf > > test case to avoid infinite loop, when the testing detects 1000 times > > retrying for reading empty events, it will directly bail out and return > > failure. This allows the Perf tool can continue its other test cases. > > Thanks, applied.
Thanks a lot, Arnaldo.
