Re: [RFC PATCH] alispinlock: acceleration from lock integration on multi-core platform

[One Thousand Gnomes]

On Wed, 6 Jan 2016 09:21:06 +0100
Peter Zijlstra <peterz@xxxxxxxxxxxxx> wrote:

> On Wed, Jan 06, 2016 at 09:16:43AM +0100, Peter Zijlstra wrote:
> > On Tue, Jan 05, 2016 at 09:42:27PM +0000, One Thousand Gnomes wrote:
> > > > It suffers the typical problems all those constructs do; namely it
> > > > wrecks accountability.
> > > 
> > > That's "government thinking" ;-) - for most real users throughput is
> > > more important than accountability. With the right API it ought to also
> > > be compile time switchable.
> > 
> > Its to do with having been involved with -rt. RT wants to do
> > accountability for such things because of PI and sorts.
> 
> Also, real people really do care about latency too, very bad worst case
> spikes to upset things.

Some yes - I'm familiar with the way some of the big financial number
crunching jobs need this. There are also people who instead care a lot
about throughput. Anything like this needs to end up with an external API
which looks the same whether the work is done via one thread or the other.

Alan
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