* James Bruce <[email protected]> wrote:
> While we're at it, isn't the comment above the wmult table incorrect?
> The multiplier is 1.25, meaning a 25% change per nice level, not 10%.
yes, the weight multiplier 1.25, but the actual difference in CPU
utilization, when running two CPU intense tasks, is ~10%:
PID USER PR NI VIRT RES SHR S %CPU %MEM TIME+ COMMAND
8246 mingo 20 0 1576 244 196 R 55 0.0 0:11.96 loop
8247 mingo 21 1 1576 244 196 R 45 0.0 0:10.52 loop
so the first task 'wins' +10% CPU utilization (relative to the 50% it
had before), the second task 'loses' -10% CPU utilization (relative to
the 50% it had before).
so what the comment says is true:
* The "10% effect" is relative and cumulative: from _any_ nice level,
* if you go up 1 level, it's -10% CPU usage, if you go down 1 level
* it's +10% CPU usage.
for there to be a ~+10% change in CPU utilization for a task that races
against another CPU-intense task there needs to be a ~25% change in the
weight.
Ingo
-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to [email protected]
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/
[Index of Archives]
[Kernel Newbies]
[Netfilter]
[Bugtraq]
[Photo]
[Stuff]
[Gimp]
[Yosemite News]
[MIPS Linux]
[ARM Linux]
[Linux Security]
[Linux RAID]
[Video 4 Linux]
[Linux for the blind]
[Linux Resources]
