> On Mar 28, 2015, at 8:16 AM, Roger Pau Monné <roger....@citrix.com> wrote: > > Hello, > > Thanks for the detailed description of the issue. I've reproduced your > benchmarks and with the hardware I've used (Core i3-5010U) I'm not able > to see this performance issue, below are the figures in my case: > [...] > > I'm Ccing feld because IIRC he found something similar on one of his > boxes, that also had VTx but no EPT (just like yours). Would it be > possible for you to try the same set of tests on a different hardware?
I think you're on to something. I copied this FreeBSD 10.1 VM to a system running the same version of Xen (and same SLES in the Dom0), but with an Opteron 2360SE CPU (which has both SVM and NPT), and it is *much* faster (and feels more responsive too): Forked, executed and destroyed 5000 processes in 5.216613 seconds. [Subsequent runs are consistently between 5.1 and 5.5 seconds.] sssd configure: 22.210u 8.751s 0:30.39 101.8% 4915+236k 0+300io 31pf+0w sssd build: 176.556u 78.846s 2:15.77 188.1% 5534+217k 49+44io 8pf+0w I'll run some more benchmarks, but I don't recall Linux VMs being noticeably different in speed between the Opteron and the Xeon systems -- I'm pretty sure it's not a case of a raw CPU power advantage. > Also, if even FreeBSD 10.1 compiled without XENHVM shows this issue it > means there's something in the generic code that doesn't work well when > running virtualized on this specific hardware, but I'm afraid figuring > it out is not trivial. One place to start would be asking on > freebsd-hackers and freebsd-virt. I suppose this performance delta with presence of EPT/NPT vs. lack thereof means it's time to take it to those lists? My next step will be to test 10.1 under KVM on the Xeon to confirm whether it's a Xen issue or strictly EPT. Thanks for the tips! -Andrew _______________________________________________ freebsd-xen@freebsd.org mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-xen To unsubscribe, send any mail to "freebsd-xen-unsubscr...@freebsd.org"
