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64-Bit Snow Leopard
- Thread starter jayducharme
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It is not only 32 GiB.
64-bit mode is ONLY needed to access more than 32 GiB FASTER.
32-bit OSX can access at least 128 gigs of memory in our tests, but there is a noticeable speed up on this machine gong to 64-bit. Most of this comes from better thread handling with more than 32 gigs memory.
If we do the same tests on a machine with less than 32 gigs of memory, there is not difference in performance.
OSX is designed extremely well such that applications are given the access they need to the processor and ram with little OS intervention. Thus, in reality it doesn't matter for 99.999% of users if the kernel is 32-bit or 64-bit.
Yeah you're right! I held down "6" and "4" from boot up until the wallpaper appeared, checked system profiler and lo and behold no 64 bit
Macbooks no matter how new will not run the 64bit kernel but that does not matter. All your 64 bit apps will run in 64bit glory... enjoy.
the 64-bit discussion sounds like it may need a sticky.
to be clear, if i'm following this correctly - basically EVERYONE will get full access to 32 & 64-bit apps no matter how they boot up. so Photoshop CS5 doesn't require you to boot into 64-bit, and it'll take full advantage of the hardware no matter which kernel you booted into? apologies in advance for not being savvy.
to be clear, if i'm following this correctly - basically EVERYONE will get full access to 32 & 64-bit apps no matter how they boot up. so Photoshop CS5 doesn't require you to boot into 64-bit, and it'll take full advantage of the hardware no matter which kernel you booted into? apologies in advance for not being savvy.
the 64-bit discussion sounds like it may need a sticky.
to be clear, if i'm following this correctly - basically EVERYONE will get full access to 32 & 64-bit apps no matter how they boot up. so Photoshop CS5 doesn't require you to boot into 64-bit, and it'll take full advantage of the hardware no matter which kernel you booted into? apologies in advance for not being savvy.
This feature debuted in Leopard (10.5) not Snow Leopard.
Apps don't need a 32-bit kernel to run in full 64-bit mode with full 64-bit memory access.
The ONLY reason to go to a 64-bit kernel is if you have more than 32 gigs of wired memory. The addressing used in the 32-bit mode adds too much overhead to more than 32 gigs of memory, especially with multiple threads, and slows down the App. For anyone with less than 32 gigs of memory you won't see any difference at all.
In fact, due to compatibility issues with drivers, I'ld definitely stick with a 32-bit kernel for the time being. This is exactly what Apple has been telling developer for a LONG TIME now.
This is not windows where in the desktop OS you couldn't access more than 3.5 gigs of memory without 64-bit. In windows this was the only reason to go to a 64-bit OS (except windows server which is 32-bit kernel, but can address more than 3.5 gigs memory).
I pressed the buttons on bootup and my 13" MBP does launch in 64bit mode but I notice no difference so I'll not bother in future.
I changed my com.apple.Boot.plist file to boot into 64-bit, found there was no noticeable difference except I now cannot launch VMWare Fusion. So I went back to 32-bit kernel.
What's the difference between a major and minor crash? Seems to me any program crashing is a major problem.
Correct the mac mini's and macbooks with Intel Core 2 Duo Processors are capable of running the Kernel Extensions but it is blocked in the firmware level so changing the boot file or holding the 6 and 4 keys down during boot up will not override the firmware settings.
Hopefully Apple will release a firmware update for these models.
Hopefully Apple will release a firmware update for these models.
Just installed the SL on my macbook pro 3,1. Found that it won't go into the 64bit regaredless (keyboard, use an utility, etc). My feeling is that Apple still does not have working drivers for the notebook in my opinion. I cannot be certain if the newer laptop (macbook pro or the latest macbooks) can run it 64bit.
That's pretty impressive! Accessing 'at least' 128GB of RAM on 32-bit Intel when the PAE only allows 64GB.
That's funny. Most tests I've seen of various OSes performance with operating system primitives showed OS X losing by a country mile to Linux and Windows.
That is a blatant lie. OS X is far more advanced than Windows, and equally advanced to Linux. The Linux distro in that test also makes a difference, as there are so many of them.
Benchmarking aside, shakenmartini is correct. Stuff like virtual memory and paging has been managed by the processor, not the operating system, since the 386. The 286 added the ability to support multiple programs on hardware.
Applications have been able to run on the "bare metal" without the intervention of the OS for a long, long time. When you run Mail.app or iChat or whatever, the switching back and forth to allow each to process is actually handled by the processor, not the OS.
Any performance degradations would come from stuff like kernel traps, usually when an application is accessing other hardware like an hd. This is where you get into stuff like database performance, where I have heard previously that OS X lags a bit. But that was years ago, and performance has been getting better and better.
Or is it an inconvenient truth?
goMac said:
Did you learn that from a cereal box?
The processor can NOT change processes without the kernel making it happen. Have you never heard of scheduler? What happens at the end of a time slice? An interrupt. And what happens during an interrupt? The kernel handler is called, and it sets the next available process to run. It does that by saving the current processes registers, stack pointer, etc, and then restoring the other processes.
The CPU can't do this. Even on a multicore, each core is running the scheduler at the end of each time slice.
Oh really? So the CPU just accesses the hard drive interface, looks at the file system, and reads the correct page in the swap file all by itself? Sorry, once again, that is the operating system.
What actually happens is that when a program tries to access a memory address that is in swap, a memory access error occurs. The kernel is called to handle it. If the address is truly invalid, the program is crashed out and terminated. If the address is just in swap, the kernel proceeds to bring the page in, change the page table to indicate a valid address, and, sends the process back on track.
Right.
At least you get that right, if somewhat obvious.
You've heard right.
Oh yeah, we've been through many marketing iterations since then, haven't we? I guess I forgot that OS X has been rebuilt from scratch many times now, each time more perfecter than the last perfect version.
Not really. If you code your app properly, it will run blazingly fast on OSX.
Linux and OSX are more or less the same as far as speed.
The big difference is making sure you code properly and use a decent compiler with the proper flags set.
A lot of "speed tests" don't take into account these sorts of things.
Amdahl is, generally speaking, quite correct (OS-level scheduling and VM, memory size limits, relatively slow syscalls on OSX, etc...). The point I've disagreed with him in the past on is the relevance of syscall performance to common application performance.
I don't disagree with any of Amdahl's post, but I would point out that OS X's reputation for poor database performance likely stems from a MySQL performance comparison done my AnandTech a few years ago that got a lot of attention in the geek community. (ref)
The performance discrepancies they noted are purely MySQL issues and it's not accurate to project them out to the general sense. Mac OS X does a poor job running MySQL because MySQL's engine relies heavily on threading. MySQL runs poorly on any OS that has high overhead for threading, not just on OS X. The MySQL developers have clearly focused on Linux (with its very lightweight threading overhead) and have not tuned its behavior for the demands of other platforms.
This is not even a deficiency in OS X, really, but more just a design decision. The flip side of the coin is that OS X has a very flexible and powerful threading model with complex scheduling policies and priority capabilities which just aren't found in the lightweight linux pthread world. The greater range of scheduling available in OS X can be a huge benefit for desktop and interactive apps, but as we see with MySQL are a big liability for any app which expects thread creation and destruction to be fast.
At my day job we use PostgreSQL as the core of our main product. Production deployment is on FreeBSD servers but we do development on OS X workstations. Comparing PostgreSQL database performance between OS X and Linux or FreeBSD shows only a thin performance gap.
The performance discrepancies they noted are purely MySQL issues and it's not accurate to project them out to the general sense. Mac OS X does a poor job running MySQL because MySQL's engine relies heavily on threading. MySQL runs poorly on any OS that has high overhead for threading, not just on OS X. The MySQL developers have clearly focused on Linux (with its very lightweight threading overhead) and have not tuned its behavior for the demands of other platforms.
This is not even a deficiency in OS X, really, but more just a design decision. The flip side of the coin is that OS X has a very flexible and powerful threading model with complex scheduling policies and priority capabilities which just aren't found in the lightweight linux pthread world. The greater range of scheduling available in OS X can be a huge benefit for desktop and interactive apps, but as we see with MySQL are a big liability for any app which expects thread creation and destruction to be fast.
At my day job we use PostgreSQL as the core of our main product. Production deployment is on FreeBSD servers but we do development on OS X workstations. Comparing PostgreSQL database performance between OS X and Linux or FreeBSD shows only a thin performance gap.
com.apple.Boot.plist
I found this on a french Forum:
edit this file
/Library/Preferences/SystemConfiguration/com.apple.Boot.plist
to add / replace:
<key>Kernel Flags</key>
<string>arch=x86_64</string>
Source http://toutlebuzz.com/snow-leopard-10a435/
It says to edit the com.apple.Boot.plist file. But I did it and still boot into 32 bit mode... according to the more-info panel anyway
--
Marc-André Léger, DESS, MScA(MIS), PhD(candidate)
--------------------------------------------------------------
Director, Léger Research Foundation
Organizer of the Hochelaga-Maisonneuve Popular University
Lecturer, University of Sherbrooke
Professor, Champlain College (Saint-Lambert)
--------------------------------------------------------------
Montreal, Quebec, Canada:+1(514)824-6302
Philadelphia, PA, USA:+1(215)543-6352
Paris, France: +33.(0)9.77.19.63.02
--------------------------------------------------------------
LinkedIn: http://www.linkedin.com/in/itriskmgr
Personal: http://www.leger.ca
Blog: http://crhoma.org/blogue
I found this on a french Forum:
edit this file
/Library/Preferences/SystemConfiguration/com.apple.Boot.plist
to add / replace:
<key>Kernel Flags</key>
<string>arch=x86_64</string>
Source http://toutlebuzz.com/snow-leopard-10a435/
It says to edit the com.apple.Boot.plist file. But I did it and still boot into 32 bit mode... according to the more-info panel anyway
--
Marc-André Léger, DESS, MScA(MIS), PhD(candidate)
--------------------------------------------------------------
Director, Léger Research Foundation
Organizer of the Hochelaga-Maisonneuve Popular University
Lecturer, University of Sherbrooke
Professor, Champlain College (Saint-Lambert)
--------------------------------------------------------------
Montreal, Quebec, Canada:+1(514)824-6302
Philadelphia, PA, USA:+1(215)543-6352
Paris, France: +33.(0)9.77.19.63.02
--------------------------------------------------------------
LinkedIn: http://www.linkedin.com/in/itriskmgr
Personal: http://www.leger.ca
Blog: http://crhoma.org/blogue
For most people, at least until a lot of 3rd party software is updated, running the 64-bit kernel isn't worthwhile since 32-bit system extensions/drivers (i.e., mouse or keyboard drivers, etc.), wont run in the 64-bit kernel.
Regardless of what kernel version your Mac is running, it'll still run 64-bit apps as full 64-bit apps.
This one-ups Windows 7 in that even if you need a 32-bit driver in Snow Leopard, you can still run your 64-bit apps (vs. Vista/Win 7 which is either all 32-bit or all 64-bit).
Regardless of what kernel version your Mac is running, it'll still run 64-bit apps as full 64-bit apps.
This one-ups Windows 7 in that even if you need a 32-bit driver in Snow Leopard, you can still run your 64-bit apps (vs. Vista/Win 7 which is either all 32-bit or all 64-bit).
I havent had to hold down the 6/4 keys more than once, and they're staying in 64 mode.
