Re: [patch] idle_task was wasting a lot of CPU

Matthew Kirkwood (weejock@ferret.lmh.ox.ac.uk)
Fri, 27 Nov 1998 12:59:05 +0000 (GMT)


On Fri, 27 Nov 1998, Andrea Arcangeli wrote:

> The first pending patch is a fix for a bug I discovered last week. The
> patch avoid the idle task to continue to run if an useful process is being
> wakenup. It make a _big_ difference. Compiling the kernel a `xload' show
> that the CPU is used at 100% all the time (5/10% kernel and the other is
> gcc). Without this patch xload is far from doing a straight line in the
> high part of the graph.

I'd often noticed this, but assumed that it was just an accounting
deficiency.

> - if (p->policy != SCHED_OTHER || p->counter > current->counter + 3)

> + if (/* idle_task == current || */ p->counter >= current->counter ||
> + p->policy != SCHED_OTHER)

Do you mean the have that comparison commented out?

Matthew.

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