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Diffstat (limited to 'Documentation/arm')
| -rw-r--r-- | Documentation/arm/CCN.txt | 59 |
1 files changed, 0 insertions, 59 deletions
diff --git a/Documentation/arm/CCN.txt b/Documentation/arm/CCN.txt deleted file mode 100644 index 15cdb7bc57c3..000000000000 --- a/Documentation/arm/CCN.txt +++ /dev/null @@ -1,59 +0,0 @@ -ARM Cache Coherent Network -========================== - -CCN-504 is a ring-bus interconnect consisting of 11 crosspoints -(XPs), with each crosspoint supporting up to two device ports, -so nodes (devices) 0 and 1 are connected to crosspoint 0, -nodes 2 and 3 to crosspoint 1 etc. - -PMU (perf) driver ------------------ - -The CCN driver registers a perf PMU driver, which provides -description of available events and configuration options -in sysfs, see /sys/bus/event_source/devices/ccn*. - -The "format" directory describes format of the config, config1 -and config2 fields of the perf_event_attr structure. The "events" -directory provides configuration templates for all documented -events, that can be used with perf tool. For example "xp_valid_flit" -is an equivalent of "type=0x8,event=0x4". Other parameters must be -explicitly specified. - -For events originating from device, "node" defines its index. - -Crosspoint PMU events require "xp" (index), "bus" (bus number) -and "vc" (virtual channel ID). - -Crosspoint watchpoint-based events (special "event" value 0xfe) -require "xp" and "vc" as as above plus "port" (device port index), -"dir" (transmit/receive direction), comparator values ("cmp_l" -and "cmp_h") and "mask", being index of the comparator mask. -Masks are defined separately from the event description -(due to limited number of the config values) in the "cmp_mask" -directory, with first 8 configurable by user and additional -4 hardcoded for the most frequent use cases. - -Cycle counter is described by a "type" value 0xff and does -not require any other settings. - -The driver also provides a "cpumask" sysfs attribute, which contains -a single CPU ID, of the processor which will be used to handle all -the CCN PMU events. It is recommended that the user space tools -request the events on this processor (if not, the perf_event->cpu value -will be overwritten anyway). In case of this processor being offlined, -the events are migrated to another one and the attribute is updated. - -Example of perf tool use: - -/ # perf list | grep ccn - ccn/cycles/ [Kernel PMU event] -<...> - ccn/xp_valid_flit,xp=?,port=?,vc=?,dir=?/ [Kernel PMU event] -<...> - -/ # perf stat -a -e ccn/cycles/,ccn/xp_valid_flit,xp=1,port=0,vc=1,dir=1/ \ - sleep 1 - -The driver does not support sampling, therefore "perf record" will -not work. Per-task (without "-a") perf sessions are not supported. |