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Groups > linux.kernel > #1741768
| From | <mike.travis@hpe.com> |
|---|---|
| Newsgroups | linux.kernel |
| Subject | [PATCH 0/4] x86/platform/UV: Update TSC support |
| Date | 2017-09-28 20:20 +0200 |
| Message-ID | <uuLq1-3SB-3@gated-at.bofh.it> (permalink) |
| Organization | linux.* mail to news gateway |
The UV BIOS goes to considerable effort to get the TSC synchronization
accurate across the entire system. Included in that are multiple chassis
that can have 32+ sockets. The architecture does support an external
high resolution clock to aid in maintaining this synchronization.
The resulting TSC accuracy set by the UV system BIOS is much better
than the generic kernel TSC ADJUST functions. This is important for
applications that read the TSC values directly for accessing data bases.
* These patches disable an assumption made by the kernel tsc sync
functions that Socket 0 in the system should have a TSC ADJUST
value of zero. This is not correct when the chassis are reset
asynchronously to each other so which TSC's should be zero is
not predictable.
* When the system BIOS determines that the TSC is not stable, it then
sets a flag so the UV kernel setup can set the "tsc is unstable"
flag. A patch now prevents the kernel from attempting to fix the
TSC causing a slew of warning messages.
* It also eliminates another avalanche of warning messages from older
BIOS that did not have the TSC ADJUST MSR (ex. >3000 msgs in a 32
socket Skylake system). It now notes this with a single warning
message and then moves on with fixing them.
--
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[PATCH 0/4] x86/platform/UV: Update TSC support <mike.travis@hpe.com> - 2017-09-28 20:20 +0200
Re: [PATCH 0/4] x86/platform/UV: Update TSC support Peter Zijlstra <peterz@infradead.org> - 2017-09-29 10:50 +0200
Re: [PATCH 0/4] x86/platform/UV: Update TSC support Mike Travis <mike.travis@hpe.com> - 2017-09-29 17:30 +0200
Re: [PATCH 0/4] x86/platform/UV: Update TSC support Peter Zijlstra <peterz@infradead.org> - 2017-09-29 18:30 +0200
Re: [PATCH 0/4] x86/platform/UV: Update TSC support Mike Travis <mike.travis@hpe.com> - 2017-09-29 19:40 +0200
Re: [PATCH 0/4] x86/platform/UV: Update TSC support Peter Zijlstra <peterz@infradead.org> - 2017-09-29 20:50 +0200
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