xfnw/plan9fox
1
0
Fork 0
Code Issues Pull requests Projects Releases Wiki Activity

disable tscticks in pc kernel (for now)

Browse source 
doesnt seem to be reliable. also, separate tsc frequency measurement
and cpu loopconst measurement. turned out with *notsc=, the simplcycles()
calls would mess up loopconst.
This commit is contained in:
cinap_lenrek 2013-06-20 02:30:17 +02:00
parent 8da4c8dcde
commit 17da3e3ff4
3 changed files with 19 additions and 14 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

2
sys/src/9/pc/archacpi.c
View file

@ -519,7 +519,5 @@ identify(void)
return 1;
if((cp = getconf("*nomp")) != nil && strcmp(cp, "0") != 0)
return 1;
if(m->havetsc)
archacpi.fastclock = tscticks;
return 0;
}

3
sys/src/9/pc/archmp.c
View file

@ -395,8 +395,5 @@ identify(void)
return 1;
}
if(m->havetsc)
archmp.fastclock = tscticks;
return 0;
}

28
sys/src/9/pc/i8253.c
View file

@ -145,12 +145,10 @@ guesscpuhz(int aalcycles)
*
*/
outb(Tmode, Latch2);
cycles(&a);
x = inb(T2cntr);
x |= inb(T2cntr)<<8;
aamloop(loops);
outb(Tmode, Latch2);
cycles(&b);
y = inb(T2cntr);
y |= inb(T2cntr)<<8;
@ -174,13 +172,25 @@ guesscpuhz(int aalcycles)
cpufreq = (vlong)loops*((aalcycles*2*Freq)/x);
m->loopconst = (cpufreq/1000)/aalcycles; /* AAM+LOOP's for 1 ms */
/* a == b means virtualbox has confused us */
if(m->havetsc && b > a){
b -= a;
b *= 2*Freq;
b /= x;
m->cyclefreq = b;
cpufreq = b;
if(m->havetsc){
aamloop(loops); /* warm up */
cycles(&a);
aamloop(loops);
cycles(&b);
aamloop(loops);
cycles(&a);
aamloop(loops);
cycles(&b);
/* a == b means virtualbox has confused us */
if(b > a){
b -= a;
b *= 2*Freq;
b /= x;
m->cyclefreq = b;
cpufreq = b;
}
}
m->cpuhz = cpufreq;