Messages in this thread | | | Date | Sat, 17 Nov 2007 05:43:33 +1030 | From | David Newall <> | Subject | Re: High priority tasks break SMP balancer? |
| |
There are a couple of points I would make about your python test harness. Your program compares real+system jiffies for both cpus; an ideal result would be 1.00. The measurement is taken over a relatively short period of approximately a half-second, and you kill the CPU hogs before taking final measurements, even wait for them to die first. You repeat this measurement, starting and killing CPU hogs each time. Why do you do that?
What happens if you start the hogs and take the baseline outside of the loop?
from __future__ import division import sys, os, time
def getCpuTimes(): cpu0 = 0 cpu1 = 1 for line in open("/proc/stat"): tokens = line.split() if tokens[0] == "cpu0": cpu0 = int(tokens[1]) + int(tokens[3]) elif tokens[0] == "cpu1": cpu1 = int(tokens[1]) + int(tokens[3]) return cpu0, cpu1
pid = os.spawnl(os.P_NOWAIT, "./priosched") baseline = getCpuTimes() while True: time.sleep(0.5) current = getCpuTimes() print "%.04f" % (current[0] - baseline[0]) / (current[1] - baseline[1])
- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
| |