diff options
Diffstat (limited to 'man7/time.7')
| -rw-r--r-- | man7/time.7 | 16 |
1 files changed, 8 insertions, 8 deletions
diff --git a/man7/time.7 b/man7/time.7 index ee0db5d..7259feb 100644 --- a/man7/time.7 +++ b/man7/time.7 @@ -5,7 +5,7 @@ .\" 2008-06-24, mtk: added some details about where jiffies come into .\" play; added section on high-resolution timers. .\" -.TH time 7 2023-01-22 "Linux man-pages 6.05.01" +.TH time 7 2023-10-31 "Linux man-pages 6.7" .SH NAME time \- overview of time and timers .SH DESCRIPTION @@ -16,7 +16,7 @@ either from a standard point in the past (see the description of the Epoch and calendar time below), or from some point (e.g., the start) in the life of a process .RI ( "elapsed time" ). -.PP +.P .I "Process time" is defined as the amount of CPU time used by a process. This is sometimes divided into @@ -58,7 +58,7 @@ a clock maintained by the kernel which measures time in .IR jiffies . The size of a jiffy is determined by the value of the kernel constant .IR HZ . -.PP +.P The value of .I HZ varies across kernel versions and hardware platforms. @@ -75,7 +75,7 @@ yielding a jiffies value of, respectively, 0.01, 0.004, or 0.001 seconds. Since Linux 2.6.20, a further frequency is available: 300, a number that divides evenly for the common video frame rates (PAL, 25 Hz; NTSC, 30 Hz). -.PP +.P The .BR times (2) system call is a special case. @@ -99,7 +99,7 @@ The values of certain clocks are virtualized by time namespaces; see .SS High-resolution timers Before Linux 2.6.21, the accuracy of timer and sleep system calls (see below) was also limited by the size of the jiffy. -.PP +.P Since Linux 2.6.21, Linux supports high-resolution timers (HRTs), optionally configurable via .BR CONFIG_HIGH_RES_TIMERS . @@ -112,14 +112,14 @@ checking the resolution returned by a call to .BR clock_getres (2) or looking at the "resolution" entries in .IR /proc/timer_list . -.PP +.P HRTs are not supported on all hardware architectures. (Support is provided on x86, ARM, and PowerPC, among others.) .SS The Epoch UNIX systems represent time in seconds since the .IR Epoch , 1970-01-01 00:00:00 +0000 (UTC). -.PP +.P A program can determine the .I "calendar time" via the @@ -159,7 +159,7 @@ Various system calls and functions allow a program to sleep .BR clock_nanosleep (2), and .BR sleep (3). -.PP +.P Various system calls allow a process to set a timer that expires at some point in the future, and optionally at repeated intervals; see |