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Something is deeply broken in OS X memory management

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Re: Something is deeply broken in OS X memory management

#191

Post by replax »

rohansingh wrote: post #60
sliverstorm wrote: post #58

Earlier quoted context omitted.

I can't believe this is actually advice, either - that's what Windows users used to say in the 90s. At least Windows, having gone through this particular growing pain, is nowadays fairly painless to reinstall. Did OSX ever improve that aspect of their product?

Yes. I reinstalled OS X on a couple machines do to various issues. I was extremely surprised at how nice the experience is. When I logged back in after the reinstall, Chrome even reopened with my old tabs in it.

Not sure if that is a good or a bad thing. Would really really annoy me, tough. If I reinstall an OS, I do it because I want a clean plate, everything back to "standard". Opening my old tabs in my browser tells me, that it kept various config/temp files, which is probably what I wanted to get rid of.

Re: Something is deeply broken in OS X memory management

#192

Post by karlshea »

polynomial wrote: post #187
thought_alarm wrote: post #59

Earlier quoted context omitted.

Yet it still swaps to disk ALL THE TIME and a new Terminal.app window can take up to 5 seconds to open. That's not swapping. That delay is /usr/bin/login searching the system logs so that it can display the date and time of your last login. Create a .hushlogin file in your home directory to prevent that.

Does this apply to iTerm as well?

Yes

Re: Something is deeply broken in OS X memory management

#193

Post by ryannielsen »

sliverstorm wrote: post #58
carguy1983 wrote: post #51

I have an 8-way Xeon Mac Pro w/ 20GB of RAM, almost half of which is 'free' at any point during the day unless I'm doing something really out of the ordinary. Yet it still swaps to disk ALL THE TIME and a new Terminal.app window can take up to 5 seconds to open. I really don't give a shit how it's not "technically" broken - that's broken from an experience point of view. And I haven't re-installed the OS (this was an…

I can't believe this is actually advice, either - that's what Windows users used to say in the 90s. At least Windows, having gone through this particular growing pain, is nowadays fairly painless to reinstall. Did OSX ever improve that aspect of their product?

1) It's never been "hard" to reinstall OS X. What was difficult last time you tried?

2) The OS reinstall path is identical to the OS upgrade path, making it very well tested. This has been the case since (IIRC) Snow Leopard.

3) The latest few generations of hardware can even (re)install the OS over the internet, meaning you don't even need to carry around media to reinstall. (Assuming you're on a fast connection or are willing to wait.)

It's entirely painless to reinstall OS X.

Re: Something is deeply broken in OS X memory management

#194

Post by msbarnett »

replax wrote: post #191
rohansingh wrote: post #60

Earlier quoted context omitted.

Yes. I reinstalled OS X on a couple machines do to various issues. I was extremely surprised at how nice the experience is. When I logged back in after the reinstall, Chrome even reopened with my old tabs in it.

Not sure if that is a good or a bad thing. Would really really annoy me, tough. If I reinstall an OS, I do it because I want a clean plate, everything back to "standard". Opening my old tabs in my browser tells me, that it kept various config/temp files, which is probably what I wanted to get rid of.

If you want to lose all of your user settings, create a new user account and nuke the old one.

If you want to replace various bits of the system, reinstall the OS.

These are different scenarios with different use-cases, and I'd argue it's a much worse idea to conflate the behaviours, as in certain other OSes, than OS X's fault for properly treating them as separate operations.

Re: Something is deeply broken in OS X memory management

#195

Post by daemeh »

I don't have any tests to prove this, but switching from a 64-bit kernel to a 32-bit one and forcing apps to run in 32-bit mode helps a lot with memory usage on OS X. You can use this app to switch apps to 32-bit: http://www.macupdate.com/app/mac/40405/sixtyfour

If you look at Windows 7 memory consumption with the same set of software you use in OS X, you'll notice memory usage is 1/2 or 1/3 on Windows compared to OS X. Maybe someone knows why that is?

Re: Something is deeply broken in OS X memory management

#196

Post by [deleted] »

spudlyo wrote: post #24
w0utert wrote: post #4

Not this again, we already went through this a few weeks ago. Back then, I thought the conclusion was that there is nothing broken about OS X memory management, and that with every 'fix' you come up with, you will just introduce another degenerate corner case. The same holds for any OS, trade-offs are made that may have some negative effect in some cases, to the benefit of the general cases. I don't recognize any of…

I don't recognize any of his symptoms anyway, and my OS X computers get pretty RAM-heavy use, with almost always a linux VM open, XCode, Safari with ~10 tabs, iTunes with a few thousand songs, etc. I think you missed a key ingredient to this problem, which is heavy disk reads caused by either spotlight or time machine. Reading a massive amount of data (that you'll probably not use again anytime soon) has the unfortun…

[deleted]

Re: Something is deeply broken in OS X memory management

#197

Post by slyrus »

newobj wrote: post #68
gurkendoktor wrote: post #8

Earlier quoted context omitted.

The thing is, Lion runs like crap without an SSD or insane amounts of RAM for many people. It doesn't help if it works for some, or even the majority. If anything, we need more people digging in OS X internals. I am sorry to use a tired analogy here, but Vista did work great for many too. I have two Macs, one brand new, one migrated from SL, and 10.7 Safari was almost unusable on both until I installed SSDs. If that…

Insane amounts? Like 16G? That I can buy for like $80?

Make that an extra $750 if you buy it built in to a new MacPro...

Re: Something is deeply broken in OS X memory management

#198

Post by nknight »

mitchty wrote: post #181
lgieron wrote: post #164

Earlier quoted context omitted.

> It's like the system discards pages of programs just because the app has been inactive for an hour or so. From what I've read, Windows memory manager does the same thing - after a while, it swaps out unused pages, even if plenty of free memory is available. I wonder what's the logic behind this - did the engineers assume that the speedup coming from more free memory being available for disk cache is worth the hassl…

The logic is for things like daemons or infrequently used processes that wake up maybe once a day. They don't need to be in ram all the time needlessly. So swapping out their memory that hasn't been used for N hours isn't a bad thing. And yes, the logic is sound, its better to use a bit of swap for an infrequent daemon and let 4-5 megs of memory be at the ready if needed than leave it in place all the time. The "spee…

> The logic is for things like daemons or infrequently used processes that wake up maybe once a day. They don't need to be in ram all the time needlessly. So swapping out their memory that hasn't been used for N hours isn't a bad thing.

It is, actually. I find such things unacceptable, be they on desktop or server use cases. I put as much or far more RAM in my systems than they will need, and I expect nothing to be swapped until it's actually full. Many other people do as well, which is why the Linux kernel devs finally started fixing the stupidity several years ago. Time for OS X to catch up.

Re: Something is deeply broken in OS X memory management

#200

Post by brown9-2 »

polynomial wrote: post #187
thought_alarm wrote: post #59

Earlier quoted context omitted.

Yet it still swaps to disk ALL THE TIME and a new Terminal.app window can take up to 5 seconds to open. That's not swapping. That delay is /usr/bin/login searching the system logs so that it can display the date and time of your last login. Create a .hushlogin file in your home directory to prevent that.

Does this apply to iTerm as well?

You can change your profile to not launch a new login shell for each window/terminal, but that might cause other issues.
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