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Diffstat (limited to 'Documentation/admin-guide/perf/imx-ddr.rst')
| -rw-r--r-- | Documentation/admin-guide/perf/imx-ddr.rst | 48 |
1 files changed, 33 insertions, 15 deletions
diff --git a/Documentation/admin-guide/perf/imx-ddr.rst b/Documentation/admin-guide/perf/imx-ddr.rst index 517a205abad6..3726a10a03ba 100644 --- a/Documentation/admin-guide/perf/imx-ddr.rst +++ b/Documentation/admin-guide/perf/imx-ddr.rst @@ -17,36 +17,54 @@ The "format" directory describes format of the config (event ID) and config1 (AXI filtering) fields of the perf_event_attr structure, see /sys/bus/event_source/ devices/imx8_ddr0/format/. The "events" directory describes the events types hardware supported that can be used with perf tool, see /sys/bus/event_source/ -devices/imx8_ddr0/events/. - e.g.:: +devices/imx8_ddr0/events/. The "caps" directory describes filter features implemented +in DDR PMU, see /sys/bus/events_source/devices/imx8_ddr0/caps/. + + .. code-block:: bash + perf stat -a -e imx8_ddr0/cycles/ cmd perf stat -a -e imx8_ddr0/read/,imx8_ddr0/write/ cmd AXI filtering is only used by CSV modes 0x41 (axid-read) and 0x42 (axid-write) to count reading or writing matches filter setting. Filter setting is various from different DRAM controller implementations, which is distinguished by quirks -in the driver. +in the driver. You also can dump info from userspace, filter in "caps" directory +indicates whether PMU supports AXI ID filter or not; enhanced_filter indicates +whether PMU supports enhanced AXI ID filter or not. Value 0 for un-supported, and +value 1 for supported. -* With DDR_CAP_AXI_ID_FILTER quirk. +* With DDR_CAP_AXI_ID_FILTER quirk(filter: 1, enhanced_filter: 0). Filter is defined with two configuration parts: --AXI_ID defines AxID matching value. --AXI_MASKING defines which bits of AxID are meaningful for the matching. - 0：corresponding bit is masked. - 1: corresponding bit is not masked, i.e. used to do the matching. + + - 0: corresponding bit is masked. + - 1: corresponding bit is not masked, i.e. used to do the matching. AXI_ID and AXI_MASKING are mapped on DPCR1 register in performance counter. When non-masked bits are matching corresponding AXI_ID bits then counter is incremented. Perf counter is incremented if - AxID && AXI_MASKING == AXI_ID && AXI_MASKING + AxID && AXI_MASKING == AXI_ID && AXI_MASKING This filter doesn't support filter different AXI ID for axid-read and axid-write event at the same time as this filter is shared between counters. - e.g.:: - perf stat -a -e imx8_ddr0/axid-read,axi_mask=0xMMMM,axi_id=0xDDDD/ cmd - perf stat -a -e imx8_ddr0/axid-write,axi_mask=0xMMMM,axi_id=0xDDDD/ cmd - - NOTE: axi_mask is inverted in userspace(i.e. set bits are bits to mask), and - it will be reverted in driver automatically. so that the user can just specify - axi_id to monitor a specific id, rather than having to specify axi_mask. - e.g.:: + + .. code-block:: bash + + perf stat -a -e imx8_ddr0/axid-read,axi_mask=0xMMMM,axi_id=0xDDDD/ cmd + perf stat -a -e imx8_ddr0/axid-write,axi_mask=0xMMMM,axi_id=0xDDDD/ cmd + + .. note:: + + axi_mask is inverted in userspace(i.e. set bits are bits to mask), and + it will be reverted in driver automatically. so that the user can just specify + axi_id to monitor a specific id, rather than having to specify axi_mask. + + .. code-block:: bash + perf stat -a -e imx8_ddr0/axid-read,axi_id=0x12/ cmd, which will monitor ARID=0x12 + +* With DDR_CAP_AXI_ID_FILTER_ENHANCED quirk(filter: 1, enhanced_filter: 1). + This is an extension to the DDR_CAP_AXI_ID_FILTER quirk which permits + counting the number of bytes (as opposed to the number of bursts) from DDR + read and write transactions concurrently with another set of data counters. |