Author Topic: Scanning priority  (Read 2329 times)

0 Members and 1 Guest are viewing this topic.

Offline Lisandro

  • Avast team
  • Certainly Bot
  • *
  • Posts: 67195
Scanning priority
« on: April 24, 2009, 09:31:55 PM »
In all Windows versions up to XP and Win2K3 server is known that the process priority settings have very little effect. So unless the process is really stuck in a tight loop, there's almost no difference if the priority is say Normal or High.

This is mostly caused by the fact that priorities only influence the thread scheduler - and not I/O.

Under Windows Vista, this should have changed. There is the concept of "low priority I/O", i.e. if a process (or thread) runs with a low priority level, the I/O requests it initiates will also have lower priority.

Is this really true, i.e., is the system able to distinguish between what needs to be done fast (such as paging) and what can wait (such as background antivirus scanning)?  ???
The best things in life are free.

CharleyO

  • Guest
Re: Scanning priority
« Reply #1 on: April 26, 2009, 06:14:49 AM »
***

Interesting question, Tech. I do not use Vista but support 2 computers that do. Hopefully, someone on here can answer this for us.


***

Offline igor

  • Avast team
  • Serious Graphoman
  • *
  • Posts: 11849
    • AVAST Software
Re: Scanning priority
« Reply #2 on: April 26, 2009, 12:25:22 PM »
I don't know if it's able to distinguish in a reasonable way - but Vlk experimented with the low-priority I/O some time ago... and found out that it slows the scan down a lot (I don't know, let's say 20 times).
So, I'm not sure it's the way to go (regarding avast!, I mean).

Offline Lisandro

  • Avast team
  • Certainly Bot
  • *
  • Posts: 67195
Re: Scanning priority
« Reply #3 on: April 26, 2009, 09:27:37 PM »
Thanks Igor... if it slow down that much, for sure, it's not the way...
The best things in life are free.