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SubjectRe: [PATCH] HZ change for ix86
Date
Horvath Karoly writes the following:
>
>Why? Each of the N processes gets the 1/N of the CPU - wheter there are
>long or short timeslices. If you have the CPU for long time, you'll miss
>it for long time...

Not 1/N, but (1-overhead)/N, where the overhead is the CPU time being used to
switch between the processes. The more you switch, the more time you spend
executing _none_ of the N processes that are so eager to be executed.

>> > Why is that a problem? Here is an example:
>> > You earn 1000$ a month. Your boss decides to pay you not monthly but weekly,
>> > and you begin to complain that you earn only 250$.

You could complain that you now have to spend 4 times as much money on
gasoline for driving to the bank to cash your paycheck 4 times as often. And
if the lines at the bank are really long, you might wish your checks were
scheduled less often, just like a CPU-hungry process wishes for long,
infrequent timeslices.

--
Alan Curry

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