Date: Sun, 28 Dec 2014 09:59:39 -0800 From: Kevin Oberman <rkoberman@gmail.com> To: Thomas Steen Rasmussen <thomas@gibfest.dk> Cc: FreeBSD Stable ML <stable@freebsd.org> Subject: Re: "random" hangs during boot, ACPI related ? Workaround problem by disabling HTT Message-ID: <CAN6yY1vCeqkn%2BL2NUHivh%2BHtbAMBBDvFOO9M_TM--DPMYZCahg@mail.gmail.com> In-Reply-To: <54A00A7A.2000100@gibfest.dk> References: <54A00A7A.2000100@gibfest.dk>
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On Sun, Dec 28, 2014 at 5:49 AM, Thomas Steen Rasmussen <thomas@gibfest.dk> wrote: > > -----BEGIN PGP SIGNED MESSAGE----- > Hash: SHA1 > > Hello list, > > I've had a problem a couple of times now that I wanted to share with > the list to see what you have to say. The problem is that FreeBSD > sometimes hangs during boot, the last line of output from the kernel > is "ACPI APIC Table: <INTEL DENLOW>" and then nothing more happens. > > This seems to be related to something not getting initialized correctly > after a soft reboot, but only sometimes. The first time I tried this it > was on > a server that has been in production for months, and suddently after a > reboot during an installworld run it froze. Even a verbose boot doesn't > reveal anything that jumps at me: http://i.imgur.com/y04ACyP.png > > Hard rebooting the server appears to solve it, until next reboot where > it may or may not happen again. > > The same problem seems to affect others. This is the thread where I > found suggestions for workarounds: https://bugs.pcbsd.org/issues/4024 > > Workarounds include disabling C3 or disabling HTT in bios. Disabling C3 > did nothing for me, but disabling HTT made the server boot successfully > again. > > The FreeBSD versions involved are 9 and 10, various versions. I've > attached /var/run/dmesg.boot from one of the servers that had the > problem a few weeks ago. On this server I've disabled HTT in the bios > which worked around the problem. > > I just bought a new server at Hetzner (the hosting provider where I am > experienzing this problem) and the server is not in production yet. I > wanted to hold off on disabling HTT to see if anyone wants me to > check something so we can get this fixed. > > Thoughts ? More info available on request. > > > Best regards, > > /Thomas Steen Rasmussen > I know that C3 (and higher) and TCC don't get along on some platforms. I thought that throttling was now off by default, but I'm not sure as I have it disabled in /boot/loader.conf: # Disable CPU throttling hint.p4tcc.0.disabled=1 hint.acpi_throttle.0.disabled=1 This will not show up until ACPI and EST come up, so it sort of fits. Whether it causes a lockup or not, disabling it is a good idea. It was intended for use as thermal management, not power management. (The 'T' in TCC (or P4TCC) is "Thermal", after all.) -- R. Kevin Oberman, Network Engineer, Retired E-mail: rkoberman@gmail.com
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