Messages in this thread | | | Date | Wed, 9 Jan 2008 06:21:44 +0100 | From | Andi Kleen <> | Subject | Re: More breakage in native_rdtsc out of line in git-x86 II |
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> I think the problem is that the vsyscall/vdso code calls it through > vread and for that it has to be exported. There seems to be also > another bug with the old style vsyscalls not using the TSC vread > that masks it on older glibc > > Stepping with gdb through old style vgettimeofday() confirms that RDTSC is > not used. > > A long time ago we had a similar problem once and it was because of a > problem exporting the vsyscall variables in vmlinux.lds.S -- looks like that > has reappeared. > > I think the new glibc shows it because it uses the vDSO not > the older vsyscall and the new vDSO probably still works. Anyways haven't > investigated why that is in detail yet, but that's a separate > regression.
Actually that seems to be because the test system using the older glibc didn't use the TSC because it was marked unstable due a unsynchronized TSC. It should not have been -- this is a Core2 dual core single socket. Will investigate later what happened there.
-Andi
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