Hi, From: Rik van Riel <[EMAIL PROTECTED]> > Hiro Yoshioka wrote: > > Howdy, > > > > MySQL 5.0.26 had some scalability issues and it solved since 5.0.32 > > http://ossipedia.ipa.go.jp/capacity/EV0612260303/ > > (written in Japanese but you may read the graph. We compared > > 5.0.24 vs 5.0.32) snip > > MySQL tries to get a mutex but it spends about 16.8% of CPU on 8 core > > machine. > > > > I think there are a lot of room to be inproved in MySQL implementation. > > That's one aspect. > > The other aspect of the problem is that when the number of > threads exceeds the number of CPU cores, Linux no longer > manages to keep the CPUs busy and we get a lot of idle time. > > On the other hand, with the number of threads being equal to > the number of CPU cores, we are 100% CPU bound...
I have a question. If so, what is the difference of kernel's view between SMP and CPU cores? Another question. When the number of threads exceeds the number of CPU cores, we may get a lot of idle time. Then a workaround of MySQL is that do not creat threads which exceeds the number of CPU cores. Is it right? Regards, Hiro -- Hiro Yoshioka CTO/Miracle Linux Corporation http://blog.miraclelinux.com/yume/ - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/