Re: [Fwd: Re: connector is missing in 2.6.12-rc2-mm1]

From: Evgeniy Polyakov
Date: Thu Apr 07 2005 - 22:48:08 EST


On Fri, 2005-04-08 at 13:32 +1000, Herbert Xu wrote:
> On Fri, Apr 08, 2005 at 07:33:58AM +0400, Evgeniy Polyakov wrote:
> > On Fri, 2005-04-08 at 12:59 +1000, Herbert Xu wrote:
> > > Evgeniy Polyakov <johnpol@xxxxxxxxxxx> wrote:
> > > >
> > > > atomic_dec_and_test() is more expensive than 2 barriers + atomic_dec(),
> > > > but in case of connector I think the price is not so high.
> > >
> > > Can you list the platforms on which this is true?
> >
> > sparc64, some mips [at least in UP].
>
> Are you sure? The implementations of atomic_sub and atomic_sub_return
> (which correspond to atomic_dec and atomic_dec_and_test) seem to be
> comparable in cost on those two architectures.

mips has additional sync.
sparc64 has 32->64 conversation on exit.

> Perhaps Dave can clarify for us about sparc64?

Dave?

> Cheers,
--
Evgeniy Polyakov

Crash is better than data corruption -- Arthur Grabowski

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