diff options
| -rw-r--r-- | share/man/man7/clocks.7 | 11 |
1 files changed, 7 insertions, 4 deletions
diff --git a/share/man/man7/clocks.7 b/share/man/man7/clocks.7 index 018bbaa..5854273 100644 --- a/share/man/man7/clocks.7 +++ b/share/man/man7/clocks.7 @@ -103,7 +103,7 @@ Applications should determine its actual frequency using .Xr sysctl 3 or by reading it from the header in the profiling data file. .It -The mc14618a clock. This is a real clock with a nominal frequency of +The mc146818a clock. This is a real clock with a nominal frequency of 32768. It is divided down to give the statistic clock and the profiling clock. It isn't available to applications. .It @@ -122,16 +122,19 @@ by applications. .It The i8254 clock. This is a real clock/timer with a nominal frequency of -1193182. It is divided down to give the scheduling clock. It isn't +1193182. It has three independent time counters to be used. +It is divided down to give the scheduling clock. It isn't available to applications. .It The TSC clock (64-bit register) on fifth-generation or later x86 systems. This is a real clock with a frequency that is equivalent to the number of cycles per second of the CPU(s). Its frequency can be found using the sysctl -.Sy machdep.tsc_freq . +.Sy machdep.tsc_freq , +if it is available. It is used to interpolate between values of the scheduling clock. -It is only available to applications in a purely machine-dependent manner. +It can be accessed using the PMIOTSTAMP request of +.Xr perfmon 4 . .El .Pp Summary: if |
