CPU usage fluctuations - Part Deux!

Instead of bumping the older thread I decided to write a new one.

I just found out something that's really annoying. Whenever I run my Antivirus, DOpus CPU usage climbs way up. Opus uses around 35%-50% of the CPU while the anti virus usually takes another 40%, which leave my computer really sluggish and unable to even play a video without skipping big time.

In a sense I'm pretty happy to have found the cause of these slowdowns, they were driving me insane!

Anyway, if I close Opus while the antivirus runs, all is fine. But the Antivirus is not the only thing affect. The TortoiseSVN cache process is also and I think all apps that work with files are too.

Using Process Monitor I found out that for every file the antivirus scans, every file an application saves, etc, Opus gets several notifications.

Here is an example. I have a clipboard manager that runs from my Z: drive and saves text I copy to the clipboard to files on that drive for later reuse. With Opus open and displaying only the C: drive, whenever my clipboard app flushes its data to disk, Process Monitor reports more than 3000 events for DOpus.exe alone! DOpus seems to be doing something for all files saved by the clipboard app, and then much more.

Is there anything that can be done to prevent Opus from doing that, aside from closing it? I managing files all day long and Opus has been a real life saver, especially since Windows Explorer in Vista is clearly targeted at brain-dead users and is full of big bugs.

I'm attaching the event log from Process Monitor where I started capture, copied text to the clipboard and quickly stopped capture. In just a few seconds, Process Monitor recorded more than 3600 events.

I hope this behavior is not "as designed"... All other file managers suck, including the new Total You-Know-What!

OpusTest.zip (111 KB)

Process Monitor won't load that log file unfortunately.

Opus watches for file changes - it has to, otherwise external changes to files wouldn't be reflected in the Lister. If your AV program is generating thousands of events then Opus has to process them all to find out whether or not it needs to update the display.

Note that in a "normal" system there are LOTS file and registry events, all the time. It's just how Windows works.

I don't think I've ever seen a situation where there were so many change going on that it caused Opus to use a lot of CPU. It could all be tied into your anti-virus program, for example if the AV program is triggering a scan of every file that Opus is notified about, inside of the dopus.exe process, then it's effectively scanning every file twice, once in the AV process and again in dopus.exe. A notification shouldn't cause a scan to happen though, unless the AV program is doing something wrong.

I use NOD32 for anti-virus and you can have it scanning the system in the background and barely notice anything is going on.

In fact, if Opus is being notified about every file that is scanned that must mean the AV program is changing the files it is scanning in some way. Scanning a file shouldn't change it (unless it has a virus that had to be removed).

Hi Jon, thanks a lot for the personal reply. :wink:

Sorry about that Process Monitor log file, I just tried it again and it loads fine here. Not sure what's wrong there.

After reading your reply and looking at Nudel's screenshots I did some more investigation. It turns out that the big CPU usage hit caused by the anti-virus comes from the fact that NOD32 was set to scan inside archives which caused a lot of activity in the Temp directory and this was picked-up by Opus.

When NOD32 hit the directory which contains daily backups of my programming stuff, Opus grabbed a lot of CPU while receiving notifications of thousands of small files getting created and deleted over and over.

Since I don't think my *.pas, *.cpp, *.h files are infected, I turned off NOD32 options to check archives and all is well now! :slight_smile:

Thanks to both of you for your comments. I really like what I've seen of Opus so far and being an old Amiga veteran, I just like saying to people that I still use Directory Opus!