diff options
| -rw-r--r-- | sys/man/8/plan9.ini | 5 | ||||
| -rw-r--r-- | sys/src/9/pc/devarch.c | 2 |
2 files changed, 6 insertions, 1 deletions
diff --git a/sys/man/8/plan9.ini b/sys/man/8/plan9.ini index 61115f7fd..48aab7f37 100644 --- a/sys/man/8/plan9.ini +++ b/sys/man/8/plan9.ini @@ -720,6 +720,11 @@ processors. Prints a summary of the multiprocessor APIC interrupt configuration. .SS \fL*nomsi=\fP Disables message signaled interrupts. +.SS \fL*notsc=\fP +Disables the use of the per processor timestamp counter registers +as high resolution clock. This option is intended for machines where +the timestamp counter rate is not constant across cores or is adjusted +dynamically by power management. .SS \fL*pcimaxbno=value\fP This puts a limit on the maximum bus number probed on a PCI bus (default 7). diff --git a/sys/src/9/pc/devarch.c b/sys/src/9/pc/devarch.c index be29eab3c..90cc2f4b9 100644 --- a/sys/src/9/pc/devarch.c +++ b/sys/src/9/pc/devarch.c @@ -797,7 +797,7 @@ cpuidentify(void) /* * if there is one, set tsc to a known value */ - if(m->cpuiddx & Tsc){ + if((m->cpuiddx & Tsc) != 0 && getconf("*notsc") == nil){ m->havetsc = 1; cycles = _cycles; if(m->cpuiddx & Cpumsr) |