On 17/08/16 20:42, Zhengyu Shen 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]> --- Changes from v2 to v3: Use WARN_ONCE instead of returning generic error values Replace CPU Notifiers with newer state machine hotplug Added additional checks on event_init for grouping and sampling Remove useless mmdc_enable_profiling function Added comments Moved start index of events from 0x01 to 0x00 Added a counter to pmu_mmdc to only stop hrtimer after all events are finished Replace readl_relaxed and writel_relaxed with readl and writel Removed duplicate update function Used devm_kasprintf when naming mmdcs probed Changes from v1 to v2: Added cpumask and migration handling support to driver Validated event during event_init Added code to properly stop counters Used perf_invalid_context instead of perf_sw_context Added hrtimer to poll for overflow Added better description Added support for multiple mmdcs
Should we move all the PMU specific code under at least CONFIG_PERF_EVENTS ? Suzuki
