On Mon, 2007-05-14 at 14:07 +0200, Nick Piggin wrote:
> On Fri, May 11, 2007 at 07:18:33PM +0200, Peter Zijlstra wrote:
> > On Fri, 2007-05-11 at 18:52 +0200, Eric Dumazet wrote:
> > >
> > > But I personally find this new rw_mutex not scalable at all if you have
> > > some
> > > writers around.
On Mon, 2007-05-14 at 13:58 +0200, Nick Piggin wrote:
> On Fri, May 11, 2007 at 05:56:21PM +0200, Ingo Molnar wrote:
> >
> > * Peter Zijlstra <[EMAIL PROTECTED]> wrote:
> >
> > > I was toying with a scalable rw_mutex and found that it gives ~10%
> > > reduction in system time on ebizzy runs (wit
On Fri, May 11, 2007 at 07:18:33PM +0200, Peter Zijlstra wrote:
> On Fri, 2007-05-11 at 18:52 +0200, Eric Dumazet wrote:
> >
> > But I personally find this new rw_mutex not scalable at all if you have
> > some
> > writers around.
> >
> > percpu_counter_sum is just a L1 cache eater, and O(NR_CPU
On Fri, May 11, 2007 at 05:56:21PM +0200, Ingo Molnar wrote:
>
> * Peter Zijlstra <[EMAIL PROTECTED]> wrote:
>
> > I was toying with a scalable rw_mutex and found that it gives ~10%
> > reduction in system time on ebizzy runs (without the MADV_FREE patch).
> >
> > 2-way x86_64 pentium D box:
>
On Sat, 12 May 2007, Eric Dumazet wrote:
Esben Nielsen a écrit :
On Sat, 12 May 2007, Peter Zijlstra wrote:
> On Sat, 2007-05-12 at 11:27 +0200, Esben Nielsen wrote:
> >
> > On Fri, 11 May 2007, Peter Zijlstra wrote:
> >
> > >
> > > I was toying with a scalable rw_mutex and found th
* Esben Nielsen <[EMAIL PROTECTED]> wrote:
> Yeah, after sending that mail I realized I accepted this fact way
> back... But I disagree in that it is easy to avoid not write-lcling
> the mm semaphore: A simple malloc() might lead to a mmap() call
> creating trouble. Am I right?
yeah - that's
On Sat, 12 May 2007, Ingo Molnar wrote:
* Esben Nielsen <[EMAIL PROTECTED]> wrote:
I notice that the rwsems used now isn't priority inversion safe (thus
destroying the perpose of having PI futexes). We thus already have a
bug in the mainline.
you see everything in black and white, ignorin
Esben Nielsen a écrit :
On Sat, 12 May 2007, Peter Zijlstra wrote:
On Sat, 2007-05-12 at 11:27 +0200, Esben Nielsen wrote:
On Fri, 11 May 2007, Peter Zijlstra wrote:
I was toying with a scalable rw_mutex and found that it gives ~10%
reduction in
system time on ebizzy runs (without the
* Esben Nielsen <[EMAIL PROTECTED]> wrote:
> I notice that the rwsems used now isn't priority inversion safe (thus
> destroying the perpose of having PI futexes). We thus already have a
> bug in the mainline.
you see everything in black and white, ignoring all the grey scales!
Upstream PI fut
On Sat, 12 May 2007, Peter Zijlstra wrote:
On Sat, 2007-05-12 at 11:27 +0200, Esben Nielsen wrote:
On Fri, 11 May 2007, Peter Zijlstra wrote:
I was toying with a scalable rw_mutex and found that it gives ~10% reduction in
system time on ebizzy runs (without the MADV_FREE patch).
You br
On Sat, 2007-05-12 at 11:27 +0200, Esben Nielsen wrote:
>
> On Fri, 11 May 2007, Peter Zijlstra wrote:
>
> >
> > I was toying with a scalable rw_mutex and found that it gives ~10%
> > reduction in
> > system time on ebizzy runs (without the MADV_FREE patch).
> >
>
> You break priority enheritan
On Fri, 11 May 2007, Peter Zijlstra wrote:
I was toying with a scalable rw_mutex and found that it gives ~10% reduction in
system time on ebizzy runs (without the MADV_FREE patch).
You break priority enheritance on user space futexes! :-(
The problems is that the futex waiter have to take
On Fri, 2007-05-11 at 18:52 +0200, Eric Dumazet wrote:
> Ingo Molnar a écrit :
> > * Peter Zijlstra <[EMAIL PROTECTED]> wrote:
> >
> >> I was toying with a scalable rw_mutex and found that it gives ~10%
> >> reduction in system time on ebizzy runs (without the MADV_FREE patch).
> >>
> >> 2-way x8
On Fri, 11 May 2007, Ingo Molnar wrote:
> given how nice this looks already, have you considered completely
> replacing rwsems with this? I suspect you could test the correctness of
> that without doing a mass API changeover, by embedding struct rw_mutex
> in struct rwsem and implementing kerne
Ingo Molnar a écrit :
* Peter Zijlstra <[EMAIL PROTECTED]> wrote:
I was toying with a scalable rw_mutex and found that it gives ~10%
reduction in system time on ebizzy runs (without the MADV_FREE patch).
2-way x86_64 pentium D box:
2.6.21
/usr/bin/time ./ebizzy -m -P
59.49user 137.74system
* Peter Zijlstra <[EMAIL PROTECTED]> wrote:
> I was toying with a scalable rw_mutex and found that it gives ~10%
> reduction in system time on ebizzy runs (without the MADV_FREE patch).
>
> 2-way x86_64 pentium D box:
>
> 2.6.21
>
> /usr/bin/time ./ebizzy -m -P
> 59.49user 137.74system 1:49.2
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