Re: 2nd round of xen benchmarking

[John Nemeth <jnemeth%cue.bc.ca@localhost>]

On Aug 23, 17:53, Manuel Bouyer wrote:
} On Wed, Aug 21, 2024 at 04:24:27PM +0200, Manuel Bouyer wrote:
} > I've run a similar benchmarck:
} > /usr/bin/time sh -c "make; make clean" in pkgsrc/devel/m4, with
} > WRKOBJDIR in tmpfs make MAKE_JOBS=1
} > This is on a Xeon E5-2637, which does have EPT, the domU has 8 vcpus and
} > 8GB RAM.
} > 
} > PV (netbsd-XEN3_DOMU.gz from the NetBSD 10.0 release)
} >       155.66 real        64.30 user        91.96 sys
} >       153.36 real        63.57 user        92.71 sys
} >       153.79 real        64.68 user        92.20 sys
} >       153.77 real        64.89 user        91.99 sys
} > 
} > PVH (netbsd-GENERIC.gz from the NetBSD 10.0 release)
} >        64.08 real        38.36 user        19.98 sys
} >        61.28 real        38.80 user        20.05 sys
} >        61.31 real        38.79 user        20.07 sys
} >        61.38 real        39.08 user        19.83 sys
} > 
} > As expected, with EPT PVH gives a good performance boost over PV.
} > I can't test bare metal as this is a production system running several VMs.
} 
} Here's some more results, from an unused machine this time.
} Hardware is a Xeon X5650, which has VT-X and EPT.
} 
} Bare metal (netbsd-GENERIC.gz from the NetBSD 10.0 release)
}        63.03 real        42.56 user        15.40 sys
}        60.31 real        43.01 user        15.14 sys
}        60.36 real        42.63 user        15.60 sys
}        60.37 real        43.12 user        15.10 sys
} 
} dom0 PV (netbsd-XEN3_DOM0.gz from the NetBSD 10.0 release)
}       366.66 real        58.14 user       320.63 sys
}       347.21 real        58.67 user       306.10 sys
}       350.79 real        57.97 user       311.53 sys
}       347.43 real        59.33 user       306.22 sys
} 
} domU PV (netbsd-XEN3_DOMU.gz from the NetBSD 10.0 release)
}       204.93 real        81.24 user       126.66 sys
}       202.91 real        81.98 user       125.97 sys
}       203.11 real        81.08 user       127.13 sys
}       203.21 real        80.95 user       127.36 sys
} 
} domU PVH (netbsd-GENERIC.gz from the NetBSD 10.0 release)
}        85.40 real        51.07 user        25.71 sys
}        80.12 real        50.95 user        26.07 sys
}        80.47 real        51.78 user        25.58 sys
}        80.53 real        51.77 user        25.62 sys
} 
} I've yet to find why PV domU is faster than dom0.
} 
} So definitively, you want a system with EPT to run virtual machines these
} days, unless you don't care about performances. PV was good when i386 was
} the norm, but for 64bit systems the performance hit is important.
} PVH is good on hardware that can run it efficiently (i.e. at last with EPT
} support). A PVH dom0 is probably something to consider, on hardware where it
} can run (AFAIK Xen still considers this as experimental).

     Is EPT a cpu flag shown by "cpuctl identify", or how do we
know when a system has it?

}-- End of excerpt from Manuel Bouyer