lkml.org 
[lkml]   [2007]   [May]   [12]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
SubjectRe: [PATCH 0/2] convert mmap_sem to a scalable rw_mutex
From
Date
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 enheritance on user space futexes! :-(
> The problems is that the futex waiter have to take the mmap_sem. And as
> your rw_mutex isn't PI enabled you get priority inversions :-(

Do note that rwsems have no PI either.
PI is not a concern for mainline - yet, I do have ideas here though.


-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/

\
 
 \ /
  Last update: 2007-05-12 12:05    [W:0.122 / U:0.048 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site