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docs/perf: Add AXI ID filter capabilities information 

Add capabilities information for AXI ID filter.

Signed-off-by: Joakim Zhang <qiangqing.zhang@nxp.com>
Signed-off-by: Will Deacon <will@kernel.org>
5.4-rM2-2.2.x-imx-squashed
Joakim Zhang 2019-11-04 07:09:20 +00:00
parent d094d32b0e
commit 9869cf739e
1 changed files with 8 additions and 4 deletions
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12
Documentation/admin-guide/perf/imx-ddr.rst
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@ -17,7 +17,8 @@ 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/.
devices/imx8_ddr0/events/. The "caps" directory describes filter features implemented
in DDR PMU, see /sys/bus/events_source/devices/imx8_ddr0/caps/.
e.g.::
perf stat -a -e imx8_ddr0/cycles/ cmd
perf stat -a -e imx8_ddr0/read/,imx8_ddr0/write/ cmd
@ -25,9 +26,12 @@ devices/imx8_ddr0/events/.
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.
@ -51,7 +55,7 @@ in the driver.
e.g.::
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.
* 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.