Hi, things are not as severe - just a hardware/configuration problem...
Best regards, Karli -------- Original Message -------- Subject: Re: [Xlab] slow pagefault on KNC Date: Mon, 17 Dec 2012 19:06:53 -0600 From: Kazutomo Yoshii <[email protected]> To: xlab at cels.anl.gov <xlab at cels.anl.gov> This only happens on particular hardware(or maybe configuration). It's approx 6 usec on normal cards, which is good. I'm tracking down what is causing this problem. - kaz On 12/17/2012 10:48 AM, Kazutomo Yoshii wrote: > Hi, > > I noticed that pagefault is very slow on KNC. It takes 850 usec > while it takes ~1 usec on Xeon, so prefaulting 1GB of memory region > takes 222 sec on KNC. > > This may not impact a big app runs for hours and hours, but I guess > this definitely affects short-lived processes or threads, which might > make MIC less fascinating. > > This could be a hardware problem(need to check Phi), a kernel bug, > or maybe sage of SMP kernel on many-core. > If this is the last case, it would be really interesting for me. > > Attached a simple page fault benchmark. > > - kaz _______________________________________________ Xlab mailing list Xlab at lists.cels.anl.gov https://lists.cels.anl.gov/mailman/listinfo/xlab
