Re: rglug: Re: Round Robin

["Sveinn í Felli (IMAP)" <sveinki ( at ) nett ( dot ) is>]

Sælt veri fólkið;

Bjarni R. Einarsson wrote:
>> 
>> Það er það sem round-robin gerir, það skiptir
>> bandvíddinni jafnt milli þeirra flokka sem eru
>> tilgreindir.  Svo er áhugaverða spurningin: hvað gerist
>> innan hvers flokks?  hvað gerist ef flokkur nýtir ekki
>> alla bandvíddina sína?

Athyglisverð spurning.
Samkvæmt dæmi á wikipediu um virkni Round Robin, gerist
þetta svona:

"Example: The time slot could be 100 milliseconds. If a job1
takes a total time of 250ms to complete, the round-robin
scheduler will suspend the job after 100ms and give other
jobs their time on the CPU. Once the other jobs have had
their equal share (100ms each), job1 will get another
allocation of CPU time and the cycle will repeat. This
process continues until the job finishes and needs no more
time on the CPU.

    * Job1 = Total time to complete 250ms (quantum 100ms).

   1. First allocation = 100ms.
   2. Second allocation = 100ms.
   3. Third allocation = 100ms but job1 self-terminates
after 50ms.
   4. Total CPU time of job1 = 250ms.

[edit] Data packet scheduling

In best-effort packet switching and other statistical
multiplexing, round-robin scheduling can be used as an
alternative to first-come first-served queuing."

Spurningin er hvort þessum afgangs 50ms í lið 3. sé
yfirhöfuð úthlutað aftur; fer það kannski eftir harðvörunni?

Er bara að eyða afgangs bandvídd :)

Sveinn í Felli