Subj : Re: Hazard Pointers w/o memory barrier. To : comp.programming.threads From : Joe Seigh Date : Wed May 04 2005 08:00 am On Tue, 03 May 2005 22:31:49 -0400, Joe Seigh wrote: > On Tue, 03 May 2005 19:13:33 -0400, Joe Seigh wrote: > >> Hmm... signals thrash things up quite a bit. Things >> slow way down unless I put the polling interval up to >> 300 msec to spread the signaling out a bit. Then I >> get about 1,286,000 reads/sec/thread for RCU+SMR vs. >> 176,000 reads/sec/thread for RCU with the same polling >> interval. It's a little over 700 reads/sec/thread for >> mutexes or rwlocks. > > Ah wait, I must have been looking at the write rate. It > gets well over 500,000 reads/sec/thread at the default > poll interval, 50 msec. That's more reasonable. Now > to try it on Linux to see how it works there. Linux > signaling is preemptive I believe. > Mystery cleared up. I was getting read rates of 9 reads/sec/thread on occasion. It seems that even though I'm using a barrier to start the readers and writers all at once, sometimes the writers can get way ahead of the readers. Increasing the duration averaged things out better. The read rates works out to be around 1,500,000+ reads/sec/thread in that case. -- Joe Seigh When you get lemons, you make lemonade. When you get hardware, you make software. .