Messages in this thread | | | Date | Tue, 18 May 2010 10:04:01 -0700 | From | "H. Peter Anvin" <> | Subject | Re: [PATCH] x86: Export tsc related information in sysfs |
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On 05/18/2010 09:52 AM, Peter Zijlstra wrote: > On Tue, 2010-05-18 at 09:40 -0700, H. Peter Anvin wrote: >> >> The problem is that you throw the baby (vsyscall) out with the bathwater >> (user rdtsc). > > Well, we could only flip the CR4 bit when we mark the TSC unsuitable for > gtod. That should be plenty good to tag all userspace trying to use it, > since more than half my machines don't use TSC for clocksource.
This might be an option, although it would have to be an *option*. There are restricted uses of the TSC in userspace which are still useful (mainly involving performance analysis and/or CPU-locked processes).
-hpa
-- H. Peter Anvin, Intel Open Source Technology Center I work for Intel. I don't speak on their behalf.
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