Virtual Memory usage

[Moshe]

This might sound a bit odd. But ever since running uTorrent, it seems that windows is constantly paging to virtual memory (hard disk) even though there is enough system ram (over 300mb free real ram) when the computer is just left alone for a while.

And by paging, I mean that all non-active applications are paged, not uTorrent itself. It's as if uTorrent is constantly trying to free up system memory, even though it barely uses any memory.

If uTorrent is indeed trying to constantly free system memory (which causes windows to write recently unused memory to the hard drive, even if there is enough free memory), please have a switch to turn off this feature.

Running on XP SP2 fully patched on a very clean system (no junk running in the background).

[Firon]

Any firewall/anti-virus program?

[Moshe]

SyGate firewall (WinXP Firewall disabled). No anti-virus running in the background.

[Firon]

Try uninstalling Sygate, I guess... It's all I can think of.

[Moshe]

Firon:

SyGate isn't something new to the system, uTorrent is... if uTorrent is calling WinAPI function that pages all unused memory, that's not a good practice (if uTorrent does it).

[Firon]

It's not. It doesn't do that on my system.

[Klaus_1250]

Moshe, can you give us a screenshot of the Task Manager with all the processes? Before tkaing the screenshot, go to View --> Select Columns and check Peak Memory Size, Virtual Memory Size and Page Faults.

[Moshe]

Since the board doesn't allow attachments, I had to use one of the free image services...

And I have disabled uTorrent for a day and everything was back to normal. As soon as I started running uTorrent again and leave it running in the background while watching some video, Windows will page to virtual memory all inactive application, even though there's over 300mb of real ram free.

Like I said previously, I'm guessing a uTorrent memory-managenet routine is calling a WinAPI function to release as much free memory as possible, even though uTorrent doesn't use it.

[Klaus_1250]

Seems fairly normal. Indeed pretty normal and clean. How much real mem do you have in total? How long have you been running your PC when you took the screenshot?

[Moshe]

512mb real ram, but as you can see from the list, barely anything is running.

The computer is running for about two days.

I just noticed something I missed earlier, the actual free memory is down to 50mb and the system cache is at nearly 400mb. It seems my assumption was wrong. uTorrent isn't asking windows for more free memory, it's somehow getting windows to cache a lot of data and then windows itself drops background applications to virtual memory to get more ram for system cache.

There's no reason uTorrent should be using window's disc cache to this extent... Maybe it's not flushing the files on write?

Also, the moment I close uTorrent, 200mb of system cache is converted into free ram (real ram, not virtual) within 3 seconds.

Side Note, I didn't override the disk cache size in uTorrent (the setting is unchecked).

Edit:

I've just raised my page file from 512mb to 1536mb to see if it would help, but I suspect there's an underlying cause making uTorrent abuse the system cache in such a way. It only happens when uTorrent is active (other P2P/BT clients don't have this effect).

[Klaus_1250]

Hmm, I remember something from the past about Windows Diskcache causing huge problems (eating up all mem). Problem is that it is not something uTorrent is doing, but it is built-in to Windows.

Check here: http://forum.utorrent.com/viewtopic.php?id=7231 and http://forum.utorrent.com/viewtopic.php?id=7424 . Pretty sure there are more threads about it.

Also, from the screenshot. You might also want to cut down on the logging of Sygate, most of the things it logs are pretty useless.

Last, if you go to Start --> Control Panel --> System --> Advanced (tab) --> Performance Settings --> Advanced, which is selected in the middle (Memory Usage): Programs or System Cache?

[Moshe]

Memory usage is set to "Programs".

I will disable most of sygate's logging, indeed, it's pretty useless, but I don't think it causes this issue.

Windows will not keep such a large disk cache when the system is pretty idle. It only reaches such large disk cache sizes when copying big files. And again, the moment uTorrent is closed, most of the system cache is cleared, this makes me assume that uTorrent is not flushing disk writes properly, so windows caches a lot of data.

It may also make a difference that I have several massive (several GBs) torrents seeding, It might somehow play into this. As having uTorrent running for 2 minutes seems enough to convert nearly all free ram into system cache.

Edit:

And yes, my problem is identical to the one described in post "http://forum.utorrent.com/viewtopic.php?id=7231".

Sadly, that thread doesn't offer a solution.

[Klaus_1250]

I'm not sure what to make of it either then :-( I have about zero system cache usuage, but am limited to 45KB/s up, so uTorrent is never really busy reading/seeding.

Perhaps a mod can comment on the status of this issue.

[Firon]

It's Windows mis-managing the system cache, not a problem with µTorrent. Go yell at Microsoft.

[tozz]

It has been a problem since uTorrent launched, it's the only program in the world I've seen that exhibits this behaviour. Devs blame Microsoft, yet this problem is limited to uTorrent.

If you want to check a little more closely, download some utils from sysinternals.com and see what happens behind the curtains.

[Switeck]

All I can think of is if half-open connections, connect rate, or max connections are set too high in µTorrent that it would eat virtual memory till something gives.

[Firon]

And Azureus used to do this to me, while µTorrent doesn't. It's a Windows problem.

[Moshe]

Just to resolve this issue. For some reason, "discio.flush_files" was set to false on my system. Setting it to true fixed the problem.

If people are having this issue with this setting enabled, it may indicate that on some systems, the flushing isn't working properly.

Although, I suspect there is an underlying problem which flushing is just a work-around. My guess is that some operation in uTorrent is causing the files not to be written properly until a flush is called. Maybe it has something to do with NTFS file system (which I'm using as I need access to files over 4gb in size and FAT32 won't allow this).