Added /proc//arch_status file, and added AVX512_elapsed_ms in
/proc//arch_status. Report it in Documentation/filesystems/proc.txt
Signed-off-by: Aubrey Li
Cc: Thomas Gleixner
Cc: Peter Zijlstra
Cc: Andi Kleen
Cc: Tim Chen
Cc: Dave Hansen
Cc: Arjan van de Ven
Cc: Alexey Dobriyan
Cc: Andrew Morton
Cc: Andy Lutomirski
Cc: Linux API
---
Documentation/filesystems/proc.txt | 37 ++
1 file changed, 37 insertions(+)
diff --git a/Documentation/filesystems/proc.txt
b/Documentation/filesystems/proc.txt
index 66cad5c86171..cf5114a8fb13 100644
--- a/Documentation/filesystems/proc.txt
+++ b/Documentation/filesystems/proc.txt
@@ -45,6 +45,7 @@ Table of Contents
3.9 /proc//map_files - Information about memory mapped files
3.10 /proc//timerslack_ns - Task timerslack value
3.11 /proc//patch_state - Livepatch patch operation state
+ 3.12 /proc//arch_status - Task architecture specific information
4Configuring procfs
4.1 Mount options
@@ -1948,6 +1949,42 @@ patched. If the patch is being enabled, then the task
has already been
patched. If the patch is being disabled, then the task hasn't been
unpatched yet.
+3.12 /proc//arch_status - task architecture specific status
+---
+When CONFIG_PROC_PID_ARCH_STATUS is enabled, this file displays the
+architecture specific status of the task.
+
+Example
+---
+ $ cat /proc/6753/arch_status
+ AVX512_elapsed_ms: 8
+
+Description
+---
+
+ AVX512_elapsed_ms:
+ --
+ If AVX512 is supported on the machine, this entry shows the milliseconds
+ elapsed since the last time AVX512 usage was recorded. The recording
+ happens on a best effort basis when a task is scheduled out. This means
+ that the value depends on two factors:
+
+1) The time which the task spent on the CPU without being scheduled
+ out. With CPU isolation and a single runnable task this can take
+ several seconds.
+
+2) The time since the task was scheduled out last. Depending on the
+ reason for being scheduled out (time slice exhausted, syscall ...)
+ this can be arbitrary long time.
+
+ As a consequence the value cannot be considered precise and authoritative
+ information. The application which uses this information has to be aware
+ of the overall scenario on the system in order to determine whether a
+ task is a real AVX512 user or not.
+
+ A special value of '-1' indicates that no AVX512 usage was recorded, thus
+ the task is unlikely an AVX512 user, but depends on the workload and the
+ scheduling scenario, it also could be a false negative mentioned above.
--
Configuring procfs
--
2.17.1
