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| 'Something is deeply broken in OS X memory management' |
| By Thom Holwerda on 2012-04-23 16:29:22 |
| Adam Fields and Perry Metzger have been investigating the serious performance issues people are experiencing with Lion. "Frequent beachballs, general overall slowness and poor UI responsivness, specific and drastic slowdowns on every Time Machine run, high memory utilization in Safari Web Content, mds, and kernel_task processes, large numbers of page outs even with a good deal of available RAM, and high amounts of RAM marked as inactive which is not readily freed back to other applications, with page outs favored." Apparently the issue is that the "virtual memory manager is bad at managing which pages should be freed from the inactive state and which ones should be paged out to disk". I won't make myself popular with a certain part of our readership, but really, is this considered a new problem? Mac OS X has always had terrible memory management, and where Windows has continuously become better at it, Mac OS X seems to have been stagnant and even getting worse. This is what happens when the company earns 2/3s of its revenue somewhere else. |
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| RE[2]: Nothing that can't be fixed |
| By AntonioTrindade on 2012-04-23 23:06:41 |
| Strange... I have no problems with wifi+bt... I use a bt mouse and WiFi all the time and stay connected all the time... :) |
 - Score: 1 |
| RE[2]: BSD Bug Reports? |
| By galvanash on 2012-04-23 23:15:02 |
|
> I'm quite sure that the memory manager of OSX wasn't derived from BSD, but from Mach. Actually, FreeBSD has adapted that memory manager, so it's rather the other way around. That was ages ago... FreeBSD inherited its Virtual Memory Management system from the original Berkeley codebase, which itself was modeled after the Mach VMM - but that was back in the 80s. Afaik the two codebases haven't seen each other for nearly 30 years. At this point I would say they are probably still architecturally similar but completely different when it comes to the nuts and bolts of how they are implemented. Mach has stagnated for the last 20 years or so - BSD has not. |
| - Score: 4 |
| RE[2]: Software engineering VS coding |
| By Alfman on 2012-04-24 03:27:30 |
|
Out of curiosity, what kind of reception would a software developer who has lived in the US for their whole career get in the European job market, say Italy or France? (Not interested in Britain if it's reputation of becoming a police state is accurate). I'm just not sure if European businesses are undergoing the same offshoring/layoff tendencies that we're seeing in the US. Can anyone with a foot on both sides of the pond shed some light on the markets relative to one another? |
| - Score: 2 |
| RE[3]: Nothing that can't be fixed |
| By looncraz on 2012-04-24 05:00:38 |
|
If you have a good amount of RAM (like what the Macs come with), then that does not occur in Windows, either. Windows 7 is the very first (non-game) Microsoft product I've ever purchased for myself and actually recommended to others. --The loon |
| - Score: 3 |
| RE[3]: Software engineering VS coding |
| By moondevil on 2012-04-24 05:29:41 |
|
> Out of curiosity, what kind of reception would a software developer who has lived in the US for their whole career get in the European job market, say Italy or France? (Not interested in Britain if it's reputation of becoming a police state is accurate). If you don't speak the country language, it is going to be very hard to get a job. English only speaking nationals, from my personal experience, are only able to find a job in big corporations working in a global market that use English as their internal working language. Some startups are open to have English only speaking workers, but they are hard to find. This is one of the reasons why most Europeans speak on average 3 languages. The mother language and two foreign languages, one of the being English. > I'm just not sure if European businesses are undergoing the same offshoring/layoff tendencies that we're seeing in the US. Can anyone with a foot on both sides of the pond shed some light on the markets relative to one another? It depends a bit where we look to. In the enterprise big companies world, is full steam ahead with offshoring, if we speak about big countries like France or Germany. You won't find any big corporation without multi-site projects, where the development takes place partially in some offshoring country. The big consultancy companies now only offer those type of projects. If on the other hand, you have a look at smaller countries, or business areas where the companies tend to be more small to medium size, then you are a bit safer from offshoring stories. The bigger issue currently, are the big corporations using the current European crisis as a way to force governments to more liberal work laws, using the competitiveness excuse, as its happening the Portugal, Spain, Greece and so on. |
| - Score: 3 |
| Um, not OS X only... |
| By remenic on 2012-04-24 06:17:16 |
|
Linux has the same problems. Try unparring and unrarring a 10GB file, and look at how all of your memory gets paged out, in favor of storing that 10GB file in file buffers. Your 8GB box will crawl. It's rediculous, but I believe it *still* happens. The kernel isn't to blame though, since it offers API's that prevent buffering/caching the file. Sadly, it's rarely used. I guess Time machine doesn't or can't similar mechanisms. API's: http://linux.die.net/man/2/madvi... MADV_DONTNEED http://linux.die.net/man/2/posix... POSIX_FADV_DONTNEED |
| - Score: 1 |
| RE: It's the paging not the MM |
| By Neolander on 2012-04-24 06:25:06 |
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I would argue that swapping (saving physical RAM pages to disk when the OS is feeling that RAM is lacking for some reason) is more guilty than paging (slicing physical memory in pages that can be put anywhere in a process' virtual address space) here. Edited 2012-04-24 06:29 UTC |
| - Score: 2 |
| RE[4]: Software engineering VS coding |
| By Neolander on 2012-04-24 06:56:06 |
|
> If you don't speak the country language, it is going to be very hard to get a job. English only speaking nationals, from my personal experience, are only able to find a job in big corporations working in a global market that use English as their internal working language. Some startups are open to have English only speaking workers, but they are hard to find. I second that, particularly in the case of France, where daily life can be a difficult if you don't know a bit of French. I'd simply add academic research jobs to the list, since it works pretty much as well as in big corporations. The thing seems to be country-dependent though. When I went to Sweden for work last year, as an example, I noticed that Swedes are much better at English than us Frenchmen. Not knowing Swedish was an annoyance, but not a crippling handicap. Edited 2012-04-24 06:56 UTC |
| - Score: 2 |
| MAC OS X Lion performance problem - broken memory manag |
| By emilio on 2012-04-24 07:02:42 |
|
I have the same problem. The inactive memory grows as i open/close applications, or surf the web etc., and the free memory shrinks. And when it falls to something like 100-150 MB, the system starts to hang, everything slows down dramatically. I finally managed to reproduce the problematic scenario, so i run the test and recorded the screen, into video. http://www.youtube.com/watch?v=u... I run the tar+bzip command, which is basic unix stuff, on the large amount of picture files, in my Pictures/ folder. Just before start, i run the "purge" command, to delete inactive/cached program data. You can see on the video that free memory starts to drop very fast, and inactive is constantly rising. When the free memory dropped below 100mb, i started some apps, like Safari, iPhoto and MS Word, and you can see in the video, that it takes even minutes (!) to start an app, when normally (when there is free RAM), it would take some 3-5 secs to load. I run the same scenario and the same commands on my Linux Centos 6 box, no problem there ! Memory usage is some 10-20mb, no problems with cache/buffer. |
| - Score: 1 |
| RE[2]: Back to the OS9 days it seems |
| By lucas_maximus on 2012-04-24 07:04:17 |
| Was it? It was a long time ago I saw it. |
| - Score: 2 |
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