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The #3 app in the mac app store is "Memory Clean", and apparently it was featured by Apple as an "invaluable utility" and won a Macworld award. This is really

by abalone 12y ago

The #3 app in the mac app store is "Memory Clean", and apparently it was featured by Apple as an "invaluable utility" and won a Macworld award. This is really strange to me because, like you, I thought OSX's native memory management ought to be optimal and tools like this are just placebos.

deleted 12y ago
[deleted]
akhatri_aus 12y ago
I've tried to observe how this app works. It actually forces OS X's native memory management to kick in. It does this by using an obscene amount of memory for a very short amount of time. This forces OS X to clean up the existing RAM in use as the RAM used by Memory Cleaner builds up dramatically. In this way its partially cosmetic since your RAM would be cleaned up if you used more of it anyway.
- kenrikm 12y ago
  There are tricks that iOS Devs (including me) use to make iOS cleanup after itself, for example iOS can take its sweet time releasing memory from MKMapViews even after the controller is gone so a trick is to switch the Map Type just before the controller is released as it forces iOS to drop the cache for the current map type. So yeah, I've not used that program but I assume it's using similar tricks in OSX.
  - lpsz 12y ago
    But that's talking about memory usage tricks within a process, which is a totally different beast from what this app claims to do.
  - abalone 12y ago
    So what exactly is the problem with it taking its "sweet time"? Isn't that just a way of saying it will wait until it actually needs the memory to drop the cache? Perhaps if there was a significant performance hit incurred when dropping caches you may want to do it more eagerly.. but is there?
xamolxix 12y ago
I use "sudo purge" from time to time. I wonder how this app is different/better.
- br0ke 12y ago
  purge(8) flushes and clears the disk buffers, which is not the issue that kills me with my old macbook with 4G ram. It looks like disk cache expiration is slow and tends to kick in when it's a bit too late. With the speed that modern apps chew through memory, I'm sent into a swap thrash and get sluggish response and beachballs. MemoryKeeper on the App store seems to mostly clear the file cache and do some -fu to compact memory (maybe it's a memory defragment, the docs are a little lacking in technical details.) When I manually run it, everything runs great until the free memory dries up and I'm back in that alloc/swapthrash/cachepurge cycle again. I wrote a tiny C program for linux to force cache expirations (in a very sloppy but reasonably portable way) back in '98 that I've started using again on osX, it fixes the issue and runs quite a bit quicker than MemoryKeeper. I can make it available if anyone else wants it.
  - hollerith 12y ago
    I'd like to see it. (my email's in my profile.)
nextw33k 12y ago
Memory management takes the form of optimism, they'll not clear down memory in case the user asks for the same thing again. For people with lots of RAM (8GB+) this is fine. However if you have a 4GB computer and generally single task, then a memory clean tool can work in your favour. I have several virtual machines that start up overnight and close down in the morning, at that point I want my memory flushed to start a fresh with my applications not the VM's cached data, which wont be needed again for another 12 hours. This is of course a corner case and just last week I upgraded to 16GB of RAM mitigating the requirement. But there is no one size fits all memory manager out there.

by abalone 12y ago

deleted 12y ago

[deleted]

akhatri_aus 12y ago

I've tried to observe how this app works. It actually forces OS X's native memory management to kick in. It does this by using an obscene amount of memory for a very short amount of time. This forces OS X to clean up the existing RAM in use as the RAM used by Memory Cleaner builds up dramatically. In this way its partially cosmetic since your RAM would be cleaned up if you used more of it anyway.

kenrikm 12y ago
There are tricks that iOS Devs (including me) use to make iOS cleanup after itself, for example iOS can take its sweet time releasing memory from MKMapViews even after the controller is gone so a trick is to switch the Map Type just before the controller is released as it forces iOS to drop the cache for the current map type. So yeah, I've not used that program but I assume it's using similar tricks in OSX.
- lpsz 12y ago
  But that's talking about memory usage tricks within a process, which is a totally different beast from what this app claims to do.
- abalone 12y ago
  So what exactly is the problem with it taking its "sweet time"? Isn't that just a way of saying it will wait until it actually needs the memory to drop the cache? Perhaps if there was a significant performance hit incurred when dropping caches you may want to do it more eagerly.. but is there?

xamolxix 12y ago

I use "sudo purge" from time to time. I wonder how this app is different/better.

br0ke 12y ago
purge(8) flushes and clears the disk buffers, which is not the issue that kills me with my old macbook with 4G ram. It looks like disk cache expiration is slow and tends to kick in when it's a bit too late. With the speed that modern apps chew through memory, I'm sent into a swap thrash and get sluggish response and beachballs. MemoryKeeper on the App store seems to mostly clear the file cache and do some -fu to compact memory (maybe it's a memory defragment, the docs are a little lacking in technical details.) When I manually run it, everything runs great until the free memory dries up and I'm back in that alloc/swapthrash/cachepurge cycle again. I wrote a tiny C program for linux to force cache expirations (in a very sloppy but reasonably portable way) back in '98 that I've started using again on osX, it fixes the issue and runs quite a bit quicker than MemoryKeeper. I can make it available if anyone else wants it.
- hollerith 12y ago
  I'd like to see it. (my email's in my profile.)

nextw33k 12y ago

Memory management takes the form of optimism, they'll not clear down memory in case the user asks for the same thing again. For people with lots of RAM (8GB+) this is fine. However if you have a 4GB computer and generally single task, then a memory clean tool can work in your favour. I have several virtual machines that start up overnight and close down in the morning, at that point I want my memory flushed to start a fresh with my applications not the VM's cached data, which wont be needed again for another 12 hours. This is of course a corner case and just last week I upgraded to 16GB of RAM mitigating the requirement. But there is no one size fits all memory manager out there.