Windows 7 On Multicore — How Much Faster? 349
snydeq writes "InfoWorld's Andrew Binstock tests whether Windows 7's threading advances fulfill the promise of improved performance and energy reduction. He runs Windows XP Professional, Vista Ultimate, and Windows 7 Ultimate against Viewperf and Cinebench benchmarks using a Dell Precision T3500 workstation, the price-performance winner of an earlier roundup of Nehalem-based workstations. 'What might be surprising is that Windows 7's multithreading changes did not deliver more of a performance punch,' Binstock writes of the benchmarks, adding that the principal changes to Windows 7 multithreading consist of increased processor affinity, 'a wholly new mechanism that gets rid of the global locking concept and pushes the management of lock access down to the locked resources,' permitting Windows 7 to scale up to 256 processors without performance penalty, but delivering little performance gains for systems with only a few processors. 'Windows 7 performs several tricks to keep threads running on the same execution pipelines so that the underlying Nehalem processor can turn off transistors on lesser-used or inactive pipelines,' Binstock writes. 'The primary benefit of this feature is reduced energy consumption,' with Windows 7 requiring 17 percent less power to run than Windows XP or Vista."
Re:Not Really (Score:5, Interesting)
What is surprising is that power consumption could be so significantly reduced. This story could have come out with an entirely different spin if the headline were simply, "Windows 7 Reduces Power Consumption by 17%."
Power savings (Score:2, Interesting)
Seeing the performance increase and in some cases decrease from Vista to 7, I don't see that as a selling feature either.
What does intrigue me is the ability of the OS to allocate threads to the different cores. That is something I would want to learn more about.
Basically, unless you're on a workstation and running intensive applications, you're not going to benefit from buying Windows 7 for an old machine.
Re:Not Really (Score:5, Interesting)
I disagree - user-mode code, whether it's separated into threads or processes, still relies very heavily on kernel scheduling decisions. It may sound simple enough, but if you study the decisions the kernel has to make (such as which thread to wake first, from a set of 8 all waiting on the same semaphore), you can find lots of ways to get it wrong. We now take it for granted because thousands of man-years have been spent on solutions.
Re:Not Really (Score:5, Interesting)
While actual performance may not be faster, perceived performance almost certianly is. It "feels" snappier, seems to respond better, due to some optimizations in locking and in the graphics subsystem that allows visual feedback in one app to not be blocked or held up by work going on in another app.
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Most interesting part uncommented... (Score:4, Interesting)
Re:Wadaya want, chopped liver? (Score:4, Interesting)
Yeah, it's possible for an OS to slow down your computer by improperly handling tasks, but you can't depend on finding and correcting them. (They may not even be there.) It's understandable to be annoyed if an OS update slows down your system; it's something else to expect a speed-up from out of nowhere.
Also, Windows 7 users are reporting a subjective improvement in response much like you report in OS X's progression.
Re:Not all code can be done in parallel (Score:3, Interesting)
And who wants to spend money looking at decades old code in order to make explicit implicit blocks, or dare to risk breakage by tweaking the code to be concurrency amenable?
Re:Windows 7 is better than Linux (Score:3, Interesting)
Re:Windows version - 7 *ULTIMATE* (Score:3, Interesting)
Re:Windows version - 7 *ULTIMATE* (Score:1, Interesting)
I agree with you in theory, but in practice it is not so clear. The server and client editions of previous Windows versions either had different kernels or different kernel tuning parameters in the registry; it is not so hard to imagine that Microsoft could extend this practice to tweak different editions of the client versions, though I am not aware of them ever doing this. Also, the different server editions have similar modifications depending on how expensive they are (i.e. how many clients can connect simultaneously, etc). In any case, I doubt there would be much of a noticeable performance difference if they did tweak the different editions.
Re:Not Really (Score:3, Interesting)
The Vista bashing was really unjustified and after you got over issues like old drivers, old hardware, and pre-SP1 UAC, you pretty much have Win7.
are you really that disillusioned? People bash Vista because it deserves it. I have Yet to run into one person that genuinely likes vista and has no problems. Out of 3 of my business clients 2 requested a downgrade to XP within the past 4 months. They both gave vista a shakedown on all workstations for 2 years, and finally looked at the numbers we gave them 6 months ago and found it cheaper to downgrade to XP than it was to stick it out. Businesses have to use legacy and really badly written software. There are 3 apps out there for sales force automation in the Cable advertising field, and all three suck because they were written in VB5. They all work well under XP but Vista64 barfs on a regular interval with them.
Then we have the Machine shop that has to use older software for their machines... You come up with a reasonable way to convince them they need to spend an additional $90,000.00 to upgrade all their machines just to use a prettied up OS in their engineering department.
Vista sucks for business, this has been known for a long time now.
Re:Something is wrong with Win7 power management (Score:5, Interesting)
The first is clearly the most desirable, as SMM is just plain wrong, and hardware protection should not rely upon the stability of the operating system.
What's happening in your case could be a problem with the EC somehow becoming confused, which is likely either a BIOS or EC firmware bug.
Re:Not all code can be done in parallel (Score:4, Interesting)
1. Parallel Software development is normally taught as a Masters Level class for computer science. Only for the last 3 years has multi-processing architecture been available for common PCs. So sorry It is not a common Skill for good parallel software development.
2. Having to rethink your coding methods isn't hard but you need to be retained to think about problems differently. Multi-Threading isn't the only thing about real parallel processing programming.
3. Spending a week to make sure your threads are completing and starting at the right time and are Not creating a race condition where you have just been lucky does require a lot of extra coding that for most applications can be the difference between the software being a benefit or a cost.
Re:Windows 7 is better than Linux (Score:5, Interesting)
Re:Less power? (Score:2, Interesting)
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