From 2e7990f87da625c99374d1a44c4709c62835e373 Mon Sep 17 00:00:00 2001 From: Thomas Gruber Date: Thu, 18 Apr 2024 13:14:32 +0200 Subject: [PATCH] Update likwidMetric.md --- collectors/likwidMetric.md | 3 +++ 1 file changed, 3 insertions(+) diff --git a/collectors/likwidMetric.md b/collectors/likwidMetric.md index 7740543..ca957d7 100644 --- a/collectors/likwidMetric.md +++ b/collectors/likwidMetric.md @@ -132,6 +132,9 @@ In some cases LIKWID returns `0.0` for some events that are further used in proc One might think this does not happen often but often used metrics in the world of performance engineering like Instructions-per-Cycle (IPC) or more frequently the actual CPU clock are derived with events like `CPU_CLK_UNHALTED_CORE` (Intel) which do not increment in halted state (as the name implies). In there are different power management systems in a chip which can cause a hardware thread to go in such a state. Moreover, if no cycles are executed by the core, also many other events are not incremented as well (like `INSTR_RETIRED_ANY` for retired instructions and part of IPC). +### `lockfile_path` option +LIKWID can be configured with a lock file with which the access to the performance monitoring registers can be disabled (only the owner of the lock file is allowed to access the registers). When the `lockfile_path` option is set, the collector subscribes to changes to this file to stop monitoring if the owner of the lock file changes. This feature is useful when users should be able to perform own hardware performance counter measurements through LIKWID or any other tool. + ### `send_*_total values` option - `send_core_total_values`: Metrics, which are usually collected on a per hardware thread basis, are additionally summed up per CPU core.