Windows 7 and Multicore
Quad core processors are typically thought of as very high end CPUs, but we’re seeing entry level quad core CPUs dipping below the $150 pin, and we’ll likely see prices heading south of $100 in the not-too-distant future. It’s also likely we’ll see quad core in mainstream notebooks, although not the thin-and-light variety, before years’ end.
On top of that, Intel has revived Hyper-Threading (simultaneous multithreading) in Core i7. The current Core i7 line supports eight threads on four cores. While many applications, as well as the OS when it multitasks, can benefit from Hyper-Threading, sometimes performance can decrease. For example, if a physical core is running a very resource intensive task, and the OS scheduler decides to schedule another processor intensive task in the virtual thread on that same core, performance can suffer.
Windows 7 ships with an improved scheduler that understands simultaneous multithreading, as well as playing better with multiple physical cores. The scheduler now understands that logical and physical cores are different, and enumerates them properly. The physical cores get priority, and the likelihood of a logical core getting slammed while the underlying physical core is very busy is now substantially decreased.
The scheduler is also smarter cores in general. For example, the scheduler will know when two active tasks are running on one core, and migrate one task to another core that’s less busy.
Finally, the Windows 7 scheduler now implements something called core parking. Windows 7 can now park or un-park a the logical processor on a particular core, as needed, to improve throughput. Resources used by the logical core can be more efficiently allocated by the physical core this way.
Last Note: Westmere is Running
Intel also noted that it’s next generation “tock” CPU, built on the upcoming 32-nm process, is actually running. They had a mobile variant of Westmere, the two-core Arandale, CPU running on a development board. Intel noted that 32nm CPUs would likely be shipping before the end of the year. Interestingly, Arandale and the desktop version, Clarkdale, will have Intel’s integrated graphics built onto the CPU package (but not the CPU die.) What that graphics will look like and perform isn’t known yet.
Westmere (Arandale) dev platform. 32nm, sooner than you think.
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6 comments
Alejandro Hernandez says:
September 1, 2009 at 6:57 pm (UTC -7 )
Oh nice, to see the new scheduler learning how to know the diference between virtual and phisical cores. Less power is ok too. But will that new CPU architecture require a new socket? cus Im still on 775 and Im planing to go i7 next holydays, should I wait?, I dont wanna get stuck on an expensive great mobo but with the wrong socket (no scalability) like happend to me on 478 times.
Loyd Case says:
September 1, 2009 at 7:24 pm (UTC -7 )
Intel is coming out with a new socket, but the old socket will be around, too. See my earlier post on Socket 1366 and 1156:
http://www.improbableinsights.com/2009/08/19/the-future-of-socket-1366/
Markeyse says:
September 1, 2009 at 9:51 pm (UTC -7 )
I can’t wait for Windows 7! And with the new Intel i5 platform right around the corner, will have a lot of possibilities. I can use a i7 chip for my professional workstation, and the i5 as a home computer.
Chris Johnson says:
September 2, 2009 at 6:16 am (UTC -7 )
Very cool stuff. Computers are so beastly hot nowadays to achieve higher and higher levels of performance. But many of us don’t need all that power all of the time. The same has been true of cars for many years. Timer coalescing actually reminds me of that Chrysler innovation where when you’re cruising on the highway the engine will shut off half the cylinders to save gas.
FH says:
September 2, 2009 at 8:24 am (UTC -7 )
Good report. Windows is a better deal on laptops/netbooks than Linux because of this, and laptops are the new majority market.
Give Apple credit, though, for having a good S3-style sleep for years, while Windows machines were hanging every time you closed the lid. There’s lot’s of history behind this New Religion.
And be ready for side effects. Do mb vendors realize they now need accurate HW clocks? Perhaps your mb coin cell won’t last long, now? Who knows?
mark says:
September 16, 2009 at 10:26 pm (UTC -7 )
Great article, I’m looking forward to 7 for a number of reasons, if it will actually have a decent sleep mode that would be great.
Any word when we might see Core i7 or i5 notebooks anytime?