Re: [PATCH] perf: Store active software events in a hashlist

From: Peter Zijlstra
Date: Wed Apr 07 2010 - 07:56:54 EST


On Wed, 2010-04-07 at 13:52 +0200, Frederic Weisbecker wrote:
> On Wed, Apr 07, 2010 at 11:02:26AM +0200, Peter Zijlstra wrote:
> > On Mon, 2010-04-05 at 16:08 +0200, Frederic Weisbecker wrote:
> > > +#define SWEVENT_HLIST_BITS 8
> > > +#define SWEVENT_HLIST_SIZE ((1 << (SWEVENT_HLIST_BITS + 1)) - 1)
> >
> > That seems to result in 9 bits worth, doesn't it?
>
>
> Oh right, I was confused, will zapp the + 1.
>

Also, what you're computing seems to be a mask, not a size

So with BITS = 8, you want
SIZE = 1<<BITS = 256
MASK = SIZE-1 = 255

right?

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