Can I use VFP in work queue context ?
nico at fluxnic.net
Thu Apr 22 15:40:46 EDT 2010
On Thu, 22 Apr 2010, Woodruff, Richard wrote:
> > From: Nicolas Pitre [mailto:nico at fluxnic.net]
> > Sent: Thursday, April 22, 2010 12:20 PM
> > > If the work queue executes in a unique context it could follow the
> > > same lazy strategy a user space one does.
> > It could... but that begs the question: what is this that requires so
> > much processing power within the kernel? This really needs to be fully
> > understood and justified before even considering a possible VFP usage in
> > the kernel.
> A simple candidate is Neon memory copy. It can perform much better
> than the ARM based one. There are a few unfortunate copies associated
> with some networking devices which see decent benefit.
The benefit is often lost when you need to defer them to a schedulable
kernel thread though.
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