On Wed, Mar 10, 2010 at 10:59:29AM +0100, Corinna Vinschen wrote: >On Mar 10 10:55, Schmidt, Oliver wrote: >> Hi Corrina, >> >> Thanks for your involvement :-) >> >> >> [...] a spinlock [...] With >> >> InterlockedCompareExchange() and Sleep() it should be quite simple to >> >> create one that's very efficient in the usual scenario. >> >> > Does the below patch fix this for you? >> >> I'll test the snapshot asap! >> >> [...] >> + LONG init = InterlockedCompareExchange (&installation_root_init, 1L, >> 0L); >> [...] >> + low_priority_sleep (0); >> [...] >> >> I see we were thinking along the same lines ;-) > >The final patch is from cgf. It's probably more performant since it >drops the requirement for an additional spinlock.
The snapshot contains try #3 on getting the locking right. I had to scrap my approach after Corinna politely reminded me that I had done something stupid in the prior snapshot. But, the spinlock approach was nothing new. We use that technique in several places in Cygwin. cgf -- Problem reports: http://cygwin.com/problems.html FAQ: http://cygwin.com/faq/ Documentation: http://cygwin.com/docs.html Unsubscribe info: http://cygwin.com/ml/#unsubscribe-simple
