From 19d0720f68c2617f1b9b686d3884333b60ca75da Mon Sep 17 00:00:00 2001
From: Jonathan Wakely <jwakely@redhat.com>
Date: Wed, 13 Nov 2024 16:47:04 +0000
Subject: [PATCH] libstdc++: Fix calculation of system time in performance
tests
The system_time() function used the wrong element of the splits array.
Also add a comment about the units for time measurements.
libstdc++-v3/ChangeLog:
* testsuite/util/testsuite_performance.h (time_counter): Add
comment about times.
(time_counter::system_time): Use correct split value.
---
libstdc++-v3/testsuite/util/testsuite_performance.h | 5 ++++-
1 file changed, 4 insertions(+), 1 deletion(-)
diff --git a/libstdc++-v3/testsuite/util/testsuite_performance.h b/libstdc++-v3/testsuite/util/testsuite_performance.h
index 4fd95b7e22a7..c2be9c8e8781 100644
--- a/libstdc++-v3/testsuite/util/testsuite_performance.h
+++ b/libstdc++-v3/testsuite/util/testsuite_performance.h
@@ -73,6 +73,9 @@ namespace __gnu_test
class time_counter
{
private:
+ // All times are measured in clock ticks.
+ // There are CLOCKS_PER_SEC ticks per second.
+ // POSIX requires CLOCKS_PER_SEC == 1000000 so ticks == microseconds.
clock_t elapsed_begin;
clock_t elapsed_end;
tms tms_begin;
@@ -136,7 +139,7 @@ namespace __gnu_test
std::size_t
system_time() const
- { return (tms_end.tms_stime - tms_begin.tms_stime) + splits[1]; }
+ { return (tms_end.tms_stime - tms_begin.tms_stime) + splits[2]; }
};
class resource_counter
--
GitLab