-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA256 On Mon, Aug 30, 2021 at 05:39:40PM -0700, Andrew David Wong wrote: > On 8/30/21 2:12 PM, haaber wrote: > > > > > > Kind of answering my own question, but disabling hyperthreading > > > > happened to > > > > be a workaround for the resume from suspend issue. > > > > > > But shouldn't hyperthreading have already been disabled ever since > > > QSB-043? > > > > > > https://www.qubes-os.org/news/2018/09/02/qsb-43/ > > > > > I admit that I missed that one as well. Shame on me. Is there some way > > to detect active hyperthreading on boot && print out a big red warning ? > > > > That seems a reasonable measure, especially for new-comers how cannot > > reasonably be asked to read all old QSB's first :) > > > > I'm confused. I was under the impression that Qubes OS (after the QSB-043 > patches) automatically disables hyper-threading for you such that you don't > have to know anything, do anything, or read any past QSBs. > > As QSB-043 explains, you would have had to follow special instructions to > re-enable hyper-threading in Qubes 3.2, and no such instructions were > provided for re-enabling it in Qubes 4.0 (since, as the QSB explains, it's > never safe in that release), so I don't even know how'd you do it in that > release. > > But perhaps I'm mistaken or misunderstanding the question.
There are (at least) two ways to disable hyper-threading: 1. In system BIOS (if there is such option) 2. In software - by disabling every second thread of each core. The QSB-043 uses the second method. It has is drawbacks, as the logic to bring up and down CPUs is quite complex. And yes, there are known issues affecting suspend. Disabling hyper-threading in BIOS, prevents Xen from starting those secondary threads at all, and so it doesn't need to bring them down.  https://github.com/QubesOS/qubes-issues/issues/6066#issuecomment-901843312 - -- Best Regards, Marek Marczykowski-Górecki Invisible Things Lab -----BEGIN PGP SIGNATURE----- iQEzBAEBCAAdFiEEhrpukzGPukRmQqkK24/THMrX1ywFAmEtfVgACgkQ24/THMrX 1yxJVgf8DMIUPdVfDjhTP6Lc/NEwIV+Fmgr0PZCa8zKQRVmKDosKH1zB2f5+fbl0 fJPygQBjx4YWu8J4p8a2kLb9T9QGRJuSFUZ1xtH0/wb5S9nZHsEEJSsFvD1NjOFN I5ynF1U+qaVbalztFSESJgRkTvTfgJLcCBT2GUvDsm6xqHEdK1BtaS0Mxogx00mQ 8xGHAUpUoC37FgLz2dSitgjmg6PzJJNiWQ14bDlKwydHy3ug9Z+fln0K9C3Pqv1s GzPs9LwM3OsNRZcKYwMNB3QGshJYIxFZMPn9s+dI9cy+DRQ6LWpGSgSdq3HLspYY MwMnD/wFxQCbNjp7c83uI7VD0wW50w== =lfCs -----END PGP SIGNATURE----- -- You received this message because you are subscribed to the Google Groups "qubes-users" group. To unsubscribe from this group and stop receiving emails from it, send an email to qubes-users+unsubscr...@googlegroups.com. To view this discussion on the web visit https://groups.google.com/d/msgid/qubes-users/YS19WGKe0oTDpKhE%40mail-itl.