At Fri, 26 Mar 2021 10:45:10 -0700, Brian Buhrow <buhrow%nfbcal.org@localhost> wrote: Subject: Re: trouble running FreeBSD with Xen-4.13 (including weird performance issues) > > hello. For what it's worth, I'm running freeBSD-12.2 as a domu > on a system with Xen-4.14.1, using FreeBSD-12.2 as the dom0. this is > in pvh mode for both host and guest. I'm not seeing any issues with > speed or reliability. For Xen, I have all the CPU mitigations turned > off, since I'm not worried about miscrient users. With them enabled, > I saw performance issues. My xen dom0 command line looks like: > > xen_cmdline="dom0_mem=8192m dom0_max_vcpus=2 dom0=pvh pv-l1tf=off,domu=off console=com1,vga com1=9600,8n1" > > I realize you're running NetBSD as dom0, but perhaps this command line > will help. I'll give the "pv-l1tf=off,domu=off" option a try on my next reboot. Thanks! That very well could be the source of the slowdown. I also see in the 4.13 xen-command-line document that there are more options to disable other mitigations as well: ssbd=force-disable spec-ctrl=no [OR spec-ctrl=no-xen] l1d-flush= srb-lock= Have you tried any of these too? There's also "vpmu=on" which might enable use of performance monitoring counters in domUs. > Also, I'm runing NetBSD-5.2, NetBSD-9 and NetBSD-current as domu's on > this system as well, all AMD64. NetBSD-5.2/i386 (32-bit) doesn't seem > to work in this environment. I've not yet investigated NetBSD-9/i386 > as yet. I forget if you've mentioned it before, but are you using any LVM volumes as storage for domUs? -- Greg A. Woods <gwoods%acm.org@localhost> Kelowna, BC +1 250 762-7675 RoboHack <woods%robohack.ca@localhost> Planix, Inc. <woods%planix.com@localhost> Avoncote Farms <woods%avoncote.ca@localhost>
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