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Consumer Products => Avast Free Antivirus / Premium Security (legacy Pro Antivirus, Internet Security, Premier) => Topic started by: patrice58 on January 25, 2009, 04:24:52 AM

Title: All about the cores
Post by: patrice58 on January 25, 2009, 04:24:52 AM

Does Avast support quad core systems, meaning does quad core systems scan faster because of the extra cores all things being equal?

Title: Re: All about the cores
Post by: alanrf on January 25, 2009, 05:14:33 AM

I recall that, in the past, the avast team said that it would use cores-1 for on demand scanning.  In other words there would be no difference in a dual core system but that cores in excess of two would be used to improve performance. 

We would have to ask the avast team to confirm if this is the case in the current release.

 

Title: Re: All about the cores
Post by: igor on January 25, 2009, 01:27:43 PM

A single scan currently uses only one core (even though you can run more scans in parallel, of course).
The bottleneck here is usually the hard disk - if it doesn't fetch the data fast enough, additional cores to process them won't really help.

Title: Re: All about the cores
Post by: patrice58 on January 25, 2009, 11:11:48 PM

Changed the question slightly

Title: Re: All about the cores
Post by: CharleyO on January 26, 2009, 07:57:25 AM

***

I think the answer igor gave above will still apply.


***

Title: Re: All about the cores
Post by: pk on January 27, 2009, 01:28:59 AM

On the contrary, on-access shield is able to scan several files in one moment -- how many it depends on your architecture/number of cores/... (usually between 4-8, I guess).

Title: Re: All about the cores
Post by: alanrf on January 27, 2009, 06:10:15 AM

pk & igor.

I think you have both answered the question but from a differing perspective.

Surely there are two cases here ... the on access scan and the on demand scan.  Please assure us that you are both trying to identify what is happening in the two different cases.

For me ... I have 5 physical drives on my dual core system.  Weekly I run two concurrent (Windows scheduled) ashquick.exe scans ... one scanning my primary C: drive and the other scan covering the other 4 drives.  The two use (no surprise) both cores and (even though I run them while having dinner) the total CPU utilization is hardly above 50% of the total of both CPUs at the times I have monitored it.         

Title: Re: All about the cores
Post by: igor on January 27, 2009, 05:22:52 PM

Well, I was trying to say that
- a single file is scanned using one core
- on-demand scan is a (serialized) sequence of single-file scans

Regarding the CPU utilization - yes, as I said, the usual bottleneck is the hard disk; CPU usually waits for the data.