> Hi, > > On Tue, Aug 30, 2016 at 07:43:29PM +0800, Shawn Guo wrote: > > On Mon, Aug 29, 2016 at 11:06:44AM -0500, Zhi Li wrote: > > > On Wed, Aug 17, 2016 at 2:42 PM, Zhengyu Shen > <[email protected]> wrote: > > > > MMDC is a multi-mode DDR controller that supports DDR3/DDR3L > > > > x16/x32/x64 and LPDDR2 two channel x16/x32 memory types. MMDC is > > > > configurable, high performance, and optimized. MMDC is present on > > > > i.MX6 Quad and i.MX6 QuadPlus devices, but this driver only supports > i.MX6 Quad at the moment. > > > > MMDC provides registers for performance counters which read via > > > > this driver to help debug memory throughput and similar issues. > > > > > > > > $ perf stat -a -e > > > > mmdc/busy-cycles/,mmdc/read-accesses/,mmdc/read- > bytes/,mmdc/total-cycles/,mmdc/write-accesses/,mmdc/write-bytes/ dd > if=/dev/zero of=/dev/null bs=1M count=5000 Performance counter stats for > 'dd if=/dev/zero of=/dev/null bs=1M count=5000': > > > > > > > > 898021787 mmdc/busy-cycles/ > > > > 14819600 mmdc/read-accesses/ > > > > 471.30 MB mmdc/read-bytes/ > > > > 2815419216 mmdc/total-cycles/ > > > > 13367354 mmdc/write-accesses/ > > > > 427.76 MB mmdc/write-bytes/ > > > > > > > > 5.334757334 seconds time elapsed > > > > > > > > Signed-off-by: Zhengyu Shen <[email protected]> > > > > Signed-off-by: Frank Li <[email protected]> > > > > > > Shawn Guo: > > > > > > No new comments got more than 1 weeks. > > > Did you plan accept it? > > > > @Mark, how do you think of this version? > > Sorry, I've been away for the last week and haven't had the chance to look at > this yet. I will try to get round to it in the next few days. > > In the meantime, could you please try attacking this with Vince's perf fuzzer > [1] (as root, or with perf_event_paranoid dropped to -1)? It's rather good at > finding (subtle) issues in drivers. > > Thanks, > Mark. > > [1] https://github.com/deater/perf_event_tests
Hi, I've done some testing with the fuzzer. Mmdc was only responsible for one crash which I fixed (had to remove the event from the pmu properly). Other drivers also cause crashes and the program reports that events are Throttling. Is this normal?
