Linked by David Adams on Wed 4th Aug 2010 18:28 UTC, submitted by estherschindler
Anyone contemplating a new computer purchase (for personal use or business) is confronted with new (and confusing) hardware choices. Intel and AMD have done their best to differentiate the x86 architecture as much as possible while retaining compatibility between the two CPUs, but the differences between the two are growing. One key differentiator is hyperthreading; Intel does it, AMD does not. This article explains what that really means, with particular attention to the way different server OSes take advantage (or don't). Plenty of meaty tech stuff.
Thread beginning with comment 435421
To read all comments associated with this story, please click here.
To read all comments associated with this story, please click here.
RE: Comment by another_sam
by Brendan on Wed 4th Aug 2010 20:22
in reply to "Comment by another_sam"
Member since:2005-11-16
Hi,
"At some point, the pipeline may stall. It has to wait for data, or for another hardware component in the computer, whatever. We’re not talking about a hung application; this is a delay of a few milliseconds while data is fetched from RAM. Still, other threads have to wait in a non-hyperthreaded pipeline, so it looks like:
thread1— thread1— (delay)— thread1—- thread2— (delay)— thread2— thread3— thread3— thread3—"
I don't get a clear picture of this added to what they told me about OS scheduling at college.
thread1— thread1— (delay)— thread1—- thread2— (delay)— thread2— thread3— thread3— thread3—"
I don't get a clear picture of this added to what they told me about OS scheduling at college.
That's because the article uses confusing terminology (I'm seriously wondering if the article's author knows the difference between hyper-threading in hardware and multi-threading in software). It's also a little misleading ("a few milliseconds while data is fetched from RAM" only makes sense if your RAM is *insanely* slow).
A (hopefully) better explanation might be:
If a core is pretending to be 2 logical CPUs; then if the core can't execute instructions from one logical CPU (e.g. because data needs to be fetched from RAM) then it can still execute instructions from the other logical CPU, and the core doesn't have to just sit there doing nothing...
-Brendan
RE[2]: Comment by another_sam
by Tuishimi on Wed 4th Aug 2010 21:32
in reply to "RE: Comment by another_sam"
Member since:2005-07-06
Member since:2009-05-12
They are talking about the processor pipeline. On a very high level, in RISC machines lets say each operation takes five cycles to complete. However one part of the cycle needs something from memory, in this case the operation cannot continue because it does not have any data. This causes a delay in the execution of the instruction. This is a level below the operating systems thread scheduler, as its the actual cpu(s) making choices on what operations are to be done.
Features
Linked by Thom Holwerda on 05/24/13 17:26 UTC
So, the Xbox One disaster continues. Microsoft's policy for dealing with the used games market has reportedly leaked - and it's a clear and direct attack to destroy the used games market. Prices for used games will be set at the retail value of a new game, and retailers have to hook into Microsoft's computer systems and comply with Microsoft's terms and conditions.
Linked by Thom Holwerda on 05/21/13 21:38 UTC
At an event earlier today, Microsoft unveiled the next Xbox - the third model, but confusingly named Xbox One. The big focus was TV, integrated Kinect, and all the other stuff we all expected to be forced down our throats. I think it took them 25 minutes to actually come to what should be the core of the story: gaming. Nothing groundbreaking in the gaming department, except for how Microsoft intends to handle the used games market and borrowing games from friends: pay up, buddy!
Linked by Thom Holwerda on 05/20/13 11:29 UTC
The day has finally come! Jolla has finally announced the launch device for its Sailfish operating system - and by god this is a looker. It's decidedly different from other phones out there, but it has good specifications and carries a relatively reasonably price tag - EUR 399, and it's up for pre-order today, shipping in the fourth quarter of this year.
Linked by Thom Holwerda on 05/18/13 21:33 UTC
Why does Google get so much credit in the technology industry? Why, despite the company's many obvious failings, do many geeks and enthusiasts still hold a somewhat positive view on the all-knowing technology giant? A specific talk at Google I/O this week provides the answer.
Linked by David Adams on 05/16/13 4:23 UTC
OSNews is a sponsor of this year's O'Reilly OSCON in Portland, Oregon, USA. A lucky OSNews reader will win a free three-day pass, including two tutorials days. To win the pass, post a comment on this story saying something about Open Source Software or OSCON. We'll pick a winner at random next week. If you don't have an OSNews account, you may email us your entry. Part of the conference is the 9th annual Open Source Awards, and today the 16th is the deadline for nominations. If you'd like to nominate an outstanding open source contributor, do it here. Read on for more information about OSCON. Update: The 20% discount code for OSNews readers is "OSN."
Linked by Thom Holwerda on 05/11/13 21:41 UTC
"Windows is indeed slower than other operating systems in many scenarios, and the gap is worsening." That's one way to start an insider explanation of why Windows' performance isn't up to snuff. Written by someone who actually contributes code to the Windows NT kernel, the comment on Hacker News, later deleted but reposted with permission on Marc Bevand's blog, paints a very dreary picture of the state of Windows development. The root issue? Think of how Linux is developed, and you'll know the answer.
Linked by Thom Holwerda on 05/08/13 14:22 UTC
This is one of those news items that's fun to write, fun to read, fun to comment on, and where no one will be able to say anything unkind. It's all just one big ball of awesome fluffiness. TuneTracker, the BeOS radio automation software, has just released something very special: TuneTracker System 5, the first version designed entirely and specifically for Haiku. In fact, it actually includes Haiku in the software package. Better yet, TuneTracker also unveiled several system-in-a-box products - which have Haiku and TuneTracker pre-installed.
Linked by Thom Holwerda on 05/02/13 15:28 UTC
Exactly twenty years ago, a document was published that played a huge role in establishing the web as we know it today. Twenty years later, and this simple and straightforward document is proof of an irrefutable fact: while closed technologies can change markets, open technologies can change the world.
Linked by Thom Holwerda on 04/29/13 21:06 UTC
Oh multitasking. That staple of computing that got thrown out the window with many modern smartphones. We got some rudimentary thing in its place - but even as multitasking on phone and tablets improves, its user-visible side remains cumbersome. Windows 8 has a neat implementation, and now it's time Android follows in it footsteps.
Linked by Thom Holwerda on 04/24/13 22:24 UTC
They're here! Whether that excites you or not remains to be seen, but the Galaxy S4, which will most likely become the best selling Android smartphone of the year by a huge margin, has been reviewed by all the major sites, and there's lots of interesting conclusions in there - although I think most of you will get the gist.More Features »
Sponsored Links
Member since:
2009-08-19
"At some point, the pipeline may stall. It has to wait for data, or for another hardware component in the computer, whatever. We’re not talking about a hung application; this is a delay of a few milliseconds while data is fetched from RAM. Still, other threads have to wait in a non-hyperthreaded pipeline, so it looks like:
thread1— thread1— (delay)— thread1—- thread2— (delay)— thread2— thread3— thread3— thread3—"
I don't get a clear picture of this added to what they told me about OS scheduling at college. I remember that was something like "when waiting for resources, the process is kicked from the CPU and put in the 'Blocked' list". See this beauty:
http://en.wikipedia.org/wiki/File:Process_states.svg
Now, according to the article, Hyperthreading is an invention for dumb OSes who are not able to put blocked processes into a 'Blocked list' out of the CPU or what?