Transmission

Does anyone else notice that Transmission chews through all of one's "free" memory and leaves them with "inactive" memory? The devs on here tell us that that is just the way OS X handles memory and that it doesn't have an impact on performance. I'm sorry but I really beg to differ. After I'm done downloading a torrent, I'm left with about 15-25MB of "free" memory and around 2.5GB of "inactive" memory. I get the beachball everywhere and the whole thing just seems to lag. I know that this happens with Vuze as well, however it doesn't happen with utorrent.

This is what my RAM looks like after a download with Transmission:


I know I can't be the only one who is experiencing this.

My system is a late 2008 Unibody MacBook, 2.4GHz and 4GB RAM.

I don't have a mac but I'm pretty sure 'Inactive' memory is actually cached data. If that's the case then I find it unlikely having high inactive memory should cause problems. You'll find that both windows and linux(unix) have the same sort of strategy with regards to how they handle virtual memory.

While you may be having some other problems on your system, the high inactive memory seems like a red herring.

I know what inactive memory is, it's just that anytime my system is low on "free" memory, it hangs and lags like I described. Transmission shouldn't use up all of the "free" memory like it does, because it DOES have an impact on performance.

If your system hangs when it's low on free memory and there's plenty of inactive memory lying around unused then there is something else going wrong with it.

I think your wrong.

And even if it was just something wrong with my system, there is no reason why Transmission should eat up all the "free" memory and leave "inactive".

The reason it 'eats' up free memory is because anything a file is read/written, OSX is going to cache it. Try copying some large files from a local hard drive to a external one and see if that 'uses' free memory.

Inactive memory is memory available to the OS. How the OS uses it is out of our control.

livings124 wrote:Inactive memory is memory available to the OS. How the OS uses it is out of our control.

Well, in principle we could fadvise(DONTNEED) any data that Transmission has touched. Under Darwin, we could also use fcntl(F_NOCACHE). Not sure whether it'd help.

--jch

jch wrote:

livings124 wrote:Inactive memory is memory available to the OS. How the OS uses it is out of our control.

Well, in principle we could fadvise(DONTNEED) any data that Transmission has touched. Under Darwin, we could also use fcntl(F_NOCACHE). Not sure whether it'd help.

--jch

That's something I would look into. There really is no need for the data that Transmission has touched to be cached. When I use µTorrent my 'inactive' memory doesn't keep growing like it does in Transmission so I wonder if they are using (DONTNEED). Also with µT, the system doesn't seem to lag either as OS X swaps 'inactive' memory for memory space needed.

Do any other Devs have an opinion or idea about this?

http://support.apple.com/kb/HT1342 :

Inactive memory

This information in memory is not actively being used, but was recently used.

For example, if you've been using Mail and then quit it, the RAM that Mail was using is marked as Inactive memory. This Inactive memory is available for use by another application, just like Free memory. However, if you open Mail before its Inactive memory is used by a different application, Mail will open quicker because its Inactive memory is converted to Active memory, instead of loading Mail from the slower hard disk.

Try giving nightly build r10901 or higher a try. I've opened a ticket to investigate the F_NOCACHE option again.

This has been tried once before around 1.50. It did seem to reduce Inactive Memory, but at the cost of making Transmission's IO more sluggish. However now that we have prefetching in place, it may be worth trying this again. See https://trac.transmissionbt.com/ticket/3371 for more background if you're interested.

I've been running r10901 for about 2 hours, and my free memory hasn't dropped.

I know this is an anecdotal enhancement, but at least it will satisfy the users who worry about these kind of things.

bitburner, do you have any news to report from testing the nightly builds?

I've been using the nightly build for 2 days now and it has been awesome, inactive memory doesn't grow out of control and the system never seems to lose it's snappiness. Before when I would Finish downloading a 4gig or so size file, I usually just let it chug along overnight, the system would be beachballing everywhere and even Apps that were already open would take a minute to load. Now everything is running like it should. I also haven't noticed transmission running any slower with it not catching the data; seems to me like prefetching in transmission is alive and working well in this build. Overall I'm really impressed with this build!