diff options
Diffstat (limited to 'Documentation/x86')
| -rw-r--r-- | Documentation/x86/intel_rdt_ui.txt | 22 |
1 files changed, 14 insertions, 8 deletions
diff --git a/Documentation/x86/intel_rdt_ui.txt b/Documentation/x86/intel_rdt_ui.txt index f662d3c530e5..52b10945ff75 100644 --- a/Documentation/x86/intel_rdt_ui.txt +++ b/Documentation/x86/intel_rdt_ui.txt @@ -520,18 +520,24 @@ the pseudo-locked region: 2) Cache hit and miss measurements using model specific precision counters if available. Depending on the levels of cache on the system the pseudo_lock_l2 and pseudo_lock_l3 tracepoints are available. - WARNING: triggering this measurement uses from two (for just L2 - measurements) to four (for L2 and L3 measurements) precision counters on - the system, if any other measurements are in progress the counters and - their corresponding event registers will be clobbered. When a pseudo-locked region is created a new debugfs directory is created for it in debugfs as /sys/kernel/debug/resctrl/<newdir>. A single write-only file, pseudo_lock_measure, is present in this directory. The -measurement on the pseudo-locked region depends on the number, 1 or 2, -written to this debugfs file. Since the measurements are recorded with the -tracing infrastructure the relevant tracepoints need to be enabled before the -measurement is triggered. +measurement of the pseudo-locked region depends on the number written to this +debugfs file: +1 - writing "1" to the pseudo_lock_measure file will trigger the latency + measurement captured in the pseudo_lock_mem_latency tracepoint. See + example below. +2 - writing "2" to the pseudo_lock_measure file will trigger the L2 cache + residency (cache hits and misses) measurement captured in the + pseudo_lock_l2 tracepoint. See example below. +3 - writing "3" to the pseudo_lock_measure file will trigger the L3 cache + residency (cache hits and misses) measurement captured in the + pseudo_lock_l3 tracepoint. + +All measurements are recorded with the tracing infrastructure. This requires +the relevant tracepoints to be enabled before the measurement is triggered. Example of latency debugging interface: In this example a pseudo-locked region named "newlock" was created. Here is |