Messages in this thread | | | Date | Tue, 5 May 2009 23:33:39 +0100 | From | Alan Cox <> | Subject | Re: [PATCH] x86: Reduce the default HZ value |
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> IMO, one of the main motives of HRT implementation apart from getting > higher precision timers was that we now don't necessarily need to rely
Timer frequency and HZ are two entirely different things nowdyas
> on a high timer frequency. If you see problems with Desktop feel and > responsiveness don't you think there would be other problem which might > be causing that ? Your argument about the "desktop feel and > responsiveness" doesn't explain what actual problem did you see.
People spent months poking at the differences before HZ=1000 became the default. It wasn't due for amusement values - but this is irrelevant anyway on a modern kernel as HZ=1000 is simply a precision setting that affects things like poll()
HZ on a tickless system has no meaningful relationship to wakup rates - which are what I assume you actually care about.
So do you want to change the precision of poll() and other functionality ? or do you want to change the wakeup rates and corresponding virtualisation overhead ?
If the latter then HZ is not the thing to touch.
What are you *actually* trying to achieve ? What measurements have you done that make you think HZ is relevant in a tickless kernel ?
Alan
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