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
