Date: Fri, 01 Aug 2014 19:13:23 +0000 From: bugzilla-noreply@freebsd.org To: freebsd-bugs@FreeBSD.org Subject: [Bug 192316] New: Invariant TSC gets misdetected on Intel Core 2 Duo processors, resulting in sluggish system behavior Message-ID: <bug-192316-8@https.bugs.freebsd.org/bugzilla/>
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https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=192316 Bug ID: 192316 Summary: Invariant TSC gets misdetected on Intel Core 2 Duo processors, resulting in sluggish system behavior Product: Base System Version: 11.0-CURRENT Hardware: Any OS: Any Status: Needs Triage Severity: Affects Some People Priority: --- Component: kern Assignee: freebsd-bugs@FreeBSD.org Reporter: jan.kokemueller@gmail.com Hi, On this Intel Core 2 Duo T6570 processor, the TSC timer gets a very high priority, even though it is not invariant. If there is power saving enabled and the processor goes to lower C-states, this results in a sluggish system. Thread on freebsd-current: https://lists.freebsd.org/pipermail/freebsd-current/2014-July/051498.html There are some Intel models hard coded as TSC invariant in the TSC detection logic, even if they are not. Suggested fix: just check if the TSC_INVARIANT processor bit is set or not. I've attached a patch. Cheers, Jan -- You are receiving this mail because: You are the assignee for the bug.
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