Hi Mathieu, Mark, On Wed, Feb 13, 2019 at 02:26:25PM -0700, Mathieu Poirier wrote: > Hi Mark, > > CoreSight trace collection is broken on v5.0-rc6 due to this commit: > > 9dff0aa95a32 perf/core: Don't WARN() for impossible ring-buffer sizes > > Before: > root@juno:/home/linaro# perf record -e cs_etm/@20070000.etr/u > --per-thread uname > [ perf record: Woken up 1 times to write data ] > [ perf record: Captured and wrote 0.036 MB perf.data ] > root@juno:/home/linaro# > > After: > root@juno:/home/linaro# perf record -e cs_etm/@20070000.etr/u > --per-thread uname > failed to mmap with 12 (Cannot allocate memory) > root@juno:/home/linaro# > > The problem is related to the order_base_2() [1] test with a size of > 1264, stemming from nr_pages equal to 128. The combination yields an > order of 11, something leading directly to the error path. > > The results are the same with linux-next 20190213. This was tested on > a Juno R0 and R1 with a 4K page configuration. I haven't tried but > I'm pretty sure it breaks IntelPT as well.
I noticed in another thread [1] Peter gave out the fixing for this issue; applied this fixing on my local code and it fixes CoreSight tracing issue. Thanks, Leo Yan [1] https://lkml.org/lkml/2019/2/12/452
