[PATCH] powerpc/64: Use tick accounting by default

[Michael Ellerman]

Anton Blanchard <anton at ozlabs.org> writes:

> From: Anton Blanchard <anton at samba.org>
>
> ppc64 is the only architecture that turns on VIRT_CPU_ACCOUNTING_NATIVE
> by default. The overhead of this option is extremely high - a context
> switch microbenchmark using sched_yield() is almost 20% slower.

Running on what? It should all be nop'ed out unless you're on a platform
that needs it (SPLPAR).

> To get finer grained user/hardirq/softirq statitics, the
> IRQ_TIME_ACCOUNTING option can be used instead, which has much lower
> overhead.

Can it? We don't select HAVE_IRQ_TIME_ACCOUNTING, so AFAICS it can't be
enabled.

Doesn't dropping this mean we never count stolen time?

cheers