Bug 64178
Summary: | Systematic clock error | ||||||
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Product: | [Retired] Red Hat Raw Hide | Reporter: | Michal Jaegermann <michal> | ||||
Component: | kernel | Assignee: | Phil Copeland <copeland> | ||||
Status: | CLOSED CURRENTRELEASE | QA Contact: | Brian Brock <bbrock> | ||||
Severity: | medium | Docs Contact: | |||||
Priority: | medium | ||||||
Version: | 1.0 | ||||||
Target Milestone: | --- | ||||||
Target Release: | --- | ||||||
Hardware: | alpha | ||||||
OS: | Linux | ||||||
Whiteboard: | |||||||
Fixed In Version: | Doc Type: | Bug Fix | |||||
Doc Text: | Story Points: | --- | |||||
Clone Of: | Environment: | ||||||
Last Closed: | 2002-04-30 21:53:36 UTC | Type: | --- | ||||
Regression: | --- | Mount Type: | --- | ||||
Documentation: | --- | CRM: | |||||
Verified Versions: | Category: | --- | |||||
oVirt Team: | --- | RHEL 7.3 requirements from Atomic Host: | |||||
Cloudforms Team: | --- | Target Upstream Version: | |||||
Embargoed: | |||||||
Attachments: |
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Description
Michal Jaegermann
2002-04-27 22:37:32 UTC
After dropping tolerances in arch/alpha/time.c from 1% to .1% I can see now while booting "HWRPB cycle frequency bogus. Estimated 796284726 Hz". This is still not perfect, as either this frequency is underestimated or time calculations are loosing precision, but much better then the current state. So far I am seeing a gain of something like 36 seconds, or maybe a bit less, for 19 hours, i.e. an error of an order of 0.05%. Moreover now this should be also tuneable with 'cycle=...' boot parameter which was impossible before (I did not try that yet). I also "backported" changes in time.c from 2.4.19pre... to 2.4.9-... as they make much more sense but tolerance limits are here really important. One percent is nearly fifteen minutes per day. A patch is attached. Created attachment 55884 [details]
A patch to make frequency estimates tighter
I've changed the cpu_hz[] table entries for EV4 and LCA4 to have a low bound of 100MHz. There were some TurboChannel machines (Pelica at least) with freq less than 150MHz Phil =--= Current release (RH 7.2 Alpha) |