lkml.org 
[lkml]   [2008]   [Mar]   [30]   [last100]   RSS Feed
Views: [more markup]  [less markup]  [headers]  [forward] 
 
Messages in this thread
/
SubjectRe: Scalability requirements for sysv ipc (+namespaces broken with SEM_UNDO)
FromMike Galbraith <>
DateSun, 30 Mar 2008 19:18:08 +0200
On Sun, 2008-03-30 at 16:12 +0200, Manfred Spraul wrote:
> Mike Galbraith wrote:
> > On Sat, 2008-03-22 at 20:08 +0100, Manfred Spraul wrote:
> >
> > 
> >> just the normal performance of 2.6.25-rc3 is abyssimal, 55 to 60% slower 
> >> than 2.6.18.8:
> >> 
> >
> > After manually reverting 3e148c79938aa39035669c1cfa3ff60722134535,
> > 2.6.25.git scaled linearly
> We can't just revert that patch: with IDR, a global lock is mandatory :-(
> We must either revert the whole idea of using IDR or live with the 
> reduced scalability.

Yeah, I looked at the problem, but didn't know what the heck to do about
it, so just grabbed my axe to verify/quantify.

> Actually, there are further bugs: the undo structures are not 
> namespace-aware, thus semop with SEM_UNDO, unshare, create new array 
> with same id, but more semaphores, another semop with SEM_UNDO will 
> corrupt kernel memory :-(
> I'll try to clean up the bugs first, then I'll look at the scalability 
> again.

Great!

	-Mike




\
 
 \ /
  Last update: 2008-03-30 18:21    [from the cache]
©2003-2008