On Mon, Jan 28, 2008 at 06:17:34PM +0100, Ingo Molnar wrote: > > * Marcelo Tosatti <[EMAIL PROTECTED]> wrote: > > > lat_ctx numbers (output is "nr-procs overhead-in-us"): > > > > cr3-cache: > > "size=0k ovr=1.30 > > 2 6.63 > > "size=0k ovr=1.31 > > 4 7.43 > > "size=0k ovr=1.32 > > 8 11.02 > > when i did the testing then i was able to get zero VM exits in the > lat_ctx hotpath and get the same performance as on native. The above > numbers you got suggest that this is not the case. (your lat_ctx numbers > on native are probably around 1 usec, right?)
Actually, native is around 5usec: # bin/x86_64-linux-gnu/lat_ctx -N 10 2 "size=0k ovr=1.09 2 5.21 So it does get pretty close to native, but the problem is that its difficult to see improvements on macrobenchmarks (even hackbench which remotely resembles a real scenario is not improving). > If that is the case, could > you check via profile=kvm (or whatever other method you use to profile > KVM) where the VM exits come from? > > Ingo > > ------------------------------------------------------------------------- > This SF.net email is sponsored by: Microsoft > Defy all challenges. Microsoft(R) Visual Studio 2008. > http://clk.atdmt.com/MRT/go/vse0120000070mrt/direct/01/ > _______________________________________________ > kvm-devel mailing list > kvm-devel@lists.sourceforge.net > https://lists.sourceforge.net/lists/listinfo/kvm-devel ------------------------------------------------------------------------- This SF.net email is sponsored by: Microsoft Defy all challenges. Microsoft(R) Visual Studio 2008. http://clk.atdmt.com/MRT/go/vse0120000070mrt/direct/01/ _______________________________________________ kvm-devel mailing list kvm-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/kvm-devel
