Date: Tue, 22 Jun 2021 19:04:34 +0000 From: bugzilla-noreply@freebsd.org To: bugs@FreeBSD.org Subject: [Bug 256781] TSC-low timecounter lags on EC2 nitro instances Message-ID: <bug-256781-227@https.bugs.freebsd.org/bugzilla/>
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https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=3D256781 Bug ID: 256781 Summary: TSC-low timecounter lags on EC2 nitro instances Product: Base System Version: 13.0-RELEASE Hardware: amd64 OS: Any Status: New Severity: Affects Only Me Priority: --- Component: kern Assignee: bugs@FreeBSD.org Reporter: martin.stoyanov@vertalo.com I am trying to use the latest FreeBSD 13 Release AMIs on EC2 and by default they start up with: kern.timecounter.hardware: TSC-low which results in a very slow clock. I did these rudimentary tests, hopefully demonstrating the problem. (all date commands were executed one minute apart after switching the timecounter. root@buildbot_master: # sysctl kern.timecounter.hardware=3Di8254 kern.timecounter.hardware: TSC-low -> i8254 root@buildbot_master: # date Tue Jun 22 18:22:45 UTC 2021 root@buildbot_master: # date Tue Jun 22 18:23:46 UTC 2021 root@buildbot_master: # sysctl kern.timecounter.hardware=3DACPI-fast kern.timecounter.hardware: i8254 -> ACPI-fast root@buildbot_master: # date Tue Jun 22 18:24:46 UTC 2021 root@buildbot_master: # date Tue Jun 22 18:25:45 UTC 2021 root@buildbot_master: # sysctl kern.timecounter.hardware=3DHPET kern.timecounter.hardware: ACPI-fast -> HPET root@buildbot_master: # date Tue Jun 22 18:26:45 UTC 2021 root@buildbot_master: # date Tue Jun 22 18:27:45 UTC 2021 root@buildbot_master:/var/service-dir # sysctl kern.timecounter.hardware=3DTSC-low kern.timecounter.hardware: HPET -> TSC-low root@buildbot_master: # date Tue Jun 22 18:28:16 UTC 2021 root@buildbot_master: # date Tue Jun 22 18:28:43 UTC 2021 This is the uname of the machine and if you need any additional info I'd be happy to provide it: root@buildbot_master: # uname -a FreeBSD buildbot_master 13.0-RELEASE-p1 FreeBSD 13.0-RELEASE-p1 #0: Wed May= 26 22:15:09 UTC 2021=20=20=20=20 root@amd64-builder.daemonology.net:/usr/obj/usr/src/amd64.amd64/sys/GENERIC= =20 amd64 --=20 You are receiving this mail because: You are the assignee for the bug.=
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