bf wrote: > > --- On Sat, 5/30/09, Kip Macy <kmacy_at_freebsd.org> wrote: > > >> From: Kip Macy <kmacy_at_freebsd.org> >> Subject: Re: signifanctly slowdown of FreeBSD 8.0-CURRENT/amd64 >> To: "bf" <bf2006a_at_yahoo.com> >> Cc: freebsd-current_at_freebsd.org, attilio_at_freebsd.org, ohartman_at_mail.zedat.fu-berlin.de >> Date: Saturday, May 30, 2009, 11:55 PM >> >>> I'm running the r193133 amd64 with a custom kernel and >>> >> all debugging off >> >>> on an AMD Athlon64 3400+ single-core, and I haven't >>> >> noticed any significant >> >>> slowing, although I haven't been doing any systematic >>> >> benchmarking. >> >>> What would be the penalties of running an SMP -CURRENT >>> >> kernel on >> >>> single-core hardware with no hyperthreading? Can >>> >> anyone quantify the >> >>> typical added overhead? Or, counterintuitively, >>> >> would an SMP kernel >> >>> be better in some ways? >>> >>> >> He is trying to diagnose if the problem was introduced by >> enabling >> adaptive spinning on sx locks. They're only enabled on SMP >> kernels. >> >> Cheers, >> Kip >> >> > > So I inferred from his request to have Oliver (the original poster) > revert r193011. But it seems unlikely that this is solely or even mostly > responsible for the slowdown, as Oliver reported that it first began > to occur several weeks ago, and Attilio only committed r193011 on Friday > -- unless Oliver independently added ADAPTIVE_SX to his custom kernel > a few weeks ago. In any event, I'm still interested in any reports of > the relative performance of SMP vs. UP kernels on UP hardware that > anyone is able to share. > > Thanks, > b. > > > > Would the addition of ADAPTIVE_SX to a SMP kernel or kernel of any kind have perfomance issues, also performance gains?Received on Mon Jun 01 2009 - 06:36:50 UTC
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