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Diffstat (limited to 'Documentation/admin-guide/perf/imx-ddr.rst')
| -rw-r--r-- | Documentation/admin-guide/perf/imx-ddr.rst | 45 |
1 files changed, 37 insertions, 8 deletions
diff --git a/Documentation/admin-guide/perf/imx-ddr.rst b/Documentation/admin-guide/perf/imx-ddr.rst index 90926d0fb8ec..77418ae5a290 100644 --- a/Documentation/admin-guide/perf/imx-ddr.rst +++ b/Documentation/admin-guide/perf/imx-ddr.rst @@ -13,8 +13,8 @@ is one register for each counter. Counter 0 is special in that it always counts interrupt is raised. If any other counter overflows, it continues counting, and no interrupt is raised. -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/ +The "format" directory describes format of the config (event ID) and config1/2 +(AXI filter setting) 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/. The "caps" directory describes filter features implemented @@ -28,12 +28,11 @@ in DDR PMU, see /sys/bus/events_source/devices/imx8_ddr0/caps/. 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. 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. +in the driver. You also can dump info from userspace, "caps" directory show the +type of AXI filter (filter, enhanced_filter and super_filter). Value 0 for +un-supported, and value 1 for supported. -* With DDR_CAP_AXI_ID_FILTER quirk(filter: 1, enhanced_filter: 0). +* With DDR_CAP_AXI_ID_FILTER quirk(filter: 1, enhanced_filter: 0, super_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. @@ -65,7 +64,37 @@ value 1 for supported. 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). +* With DDR_CAP_AXI_ID_FILTER_ENHANCED quirk(filter: 1, enhanced_filter: 1, super_filter: 0). 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. + +* With DDR_CAP_AXI_ID_PORT_CHANNEL_FILTER quirk(filter: 0, enhanced_filter: 0, super_filter: 1). + There is a limitation in previous AXI filter, it cannot filter different IDs + at the same time as the filter is shared between counters. This quirk is the + extension of AXI ID filter. One improvement is that counter 1-3 has their own + filter, means that it supports concurrently filter various IDs. Another + improvement is that counter 1-3 supports AXI PORT and CHANNEL selection. Support + selecting address channel or data channel. + + Filter is defined with 2 configuration registers per counter 1-3. + --Counter N MASK COMP register - including AXI_ID and AXI_MASKING. + --Counter N MUX CNTL register - including AXI CHANNEL and AXI PORT. + + - 0: address channel + - 1: data channel + + PMU in DDR subsystem, only one single port0 exists, so axi_port is reserved + which should be 0. + + .. code-block:: bash + + perf stat -a -e imx8_ddr0/axid-read,axi_mask=0xMMMM,axi_id=0xDDDD,axi_channel=0xH/ cmd + perf stat -a -e imx8_ddr0/axid-write,axi_mask=0xMMMM,axi_id=0xDDDD,axi_channel=0xH/ cmd + + .. note:: + + axi_channel is inverted in userspace, and it will be reverted in driver + automatically. So that users do not need specify axi_channel if want to + monitor data channel from DDR transactions, since data channel is more + meaningful. |