Dual Cores and Power Management

From the first time we heard the name Yonah we knew that its designers would be introducing some interesting power management technologies. While we don't normally like filling articles with quotes, here's one from Mooly today that is a great segway into this section:

"Yonah battery life will not be shorter than Dothan battery life...[it's] a huge achievement"

Given that Yonah will have twice the decode/execution transistors of Dothan, offering equal battery life for Yonah notebooks is a pretty impressive claim.

Mooly went through some of the power management technologies in Yonah that Intel is calling Dynamic Power Coordination. The idea is this - there are some areas where you can have each core operate independently with regards to reducing power consumption, but other areas where you can't.

Dothan has five operating states:

C0 - full power
C1 - auto halt (less power)
C2 - stop clock (even lower power)
C3 - sleep (lower power)
C4 - deep sleep (still lower)

The CPU's goal is to complete the tasks it's given, while always striving to be in as low of a power state as possible. So for example, if a Dothan is running an application that doesn't require full performance, it can operate in one of the lighter power saving states until it is done working, then eventually drop all the way down to C4.

The lighter power saving stages just do things like reduce clock speed or gate the clocks to parts of the chip, these types of things can be done independently on each core in Yonah (e.g. one core can be in C1 while the other core is in C0). Once you get down to adjusting voltage and playing with the PLL, then the two cores can't act independently - since they are both fed the same voltage and clock signal. Here is where Intel's Dynamic Power Coordination comes into play; if one CPU wants to go to a lower power state (e.g. C3 or C4) but the other core is running at C0, it will inform Intel's DPC logic of the current situation. Intel's logic, as you would expect it to act, will wait until the core running in C0 is done working and then move both cores down to the lower power state. Synchronization like this is important and it helps keep power consumption down to a minimum.

Because of the power management that is needed for Yonah, the two cores have to always work closely together to make sure that they are aware of each other's power state desires - for this reason alone Yonah is already much more than a pair of Dothans with a shared cache.

Yonah also introduces finer grained thermal management through what they are calling the Advanced Thermal Manager. With dedicated digital thermal sensors in each core, each with a higher accuracy, the temperature data the CPU can feed the rest of the system is more accurate in Yonah than in previous generation Pentium M CPUs. Although Mooly didn't talk about it here, you can expect that the thermal management technology in Yonah will allow for one core to be slowed down independently of the other if power consumption or heat dissipation rises too much.

Index Other Facts about Yonah
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  • PentiumIV - Wednesday, March 16, 2005 - link

    Banias - there is a rever in Golan Heights called Banias (or waterfall, don't remember ...)

    Dothan - there is a Dothan Valley in Israel.

    P.S. We've go a great honor- to use Israeli names for code names !
    Reply
  • PentiumIV - Wednesday, March 16, 2005 - link

    Yonah als means "pidgeon" in Hebrew .... Reply
  • PeteRoy - Friday, March 04, 2005 - link

    I think your right Determinant about that, Yonah can be a person name they call the core after.

    Dothan has no meaning in Hebrew but some people in Israel are called Dothan, I don't know about Banias.
    Reply
  • IntelUser2000 - Thursday, March 03, 2005 - link

    LOL, its so funny to see people going religiously over some computer hardware. Not that I am not an enthusiast, but not so into like most of you guys do.

    Anyways Yonah looks slick.
    Reply
  • Determinant - Thursday, March 03, 2005 - link

    #11 (PeteRoy)

    While Yona might mean pigeon in Hebrew, Yonah does not.

    Yonah means Jonah in Hebrew.

    God told the prophet Jonah to go and tell this
    one nation to change from their evil ways
    otherwise they will get punished.

    Yonah didn't listen and took a boat in the
    opposite direction. He got thrown off the boat,
    swallowed by a whale and taken to the place where
    he was supposed to go. The whale vomitted Jonah
    out.

    I think Jonah's branch predictor needed some fine
    tuning otherwise he wouldn't have made the wrong
    choice.

    Dual cores wouldn't have helped here.
    Reply
  • stephenbrooks - Thursday, March 03, 2005 - link

    #11, did the pigeon get swallowed by a whale? Did it have dual-cores? Reply
  • val - Thursday, March 03, 2005 - link

    advertising is required in current world.
    The world which cannot alive without "women intim products" ads have many reasons why so fast developing company as Intel need to advertise.
    If they will not, somebody else will. Without ads the average Joe will not know there there is something to change his PIII 700 MHz for on the market, will never know difference between garage PC and high quality laptop, etc.

    There are no bad and good guys in Capitalism. Everybody works for moneys and fame.
    Reply
  • Quanticles - Thursday, March 03, 2005 - link

    AMD is on a much tighter budget. That means they have to choose between spending money on a competitive product, or spending money on advertising. I wouldnt be suprised if Intel's advertising budget is bigger than that of AMD's entire processor division. Reply
  • Doormat - Thursday, March 03, 2005 - link

    AMD ususally has some sort of meeting around IDF. This year they didnt unveil anything new, just had lots of dual core computers running. Apparently production models too, it came out that AMD's dual core speeds will start at 2.4GHz, maybe higher (for reference, a single core 2.4GHz dual channel ddr/1MB L2 is AMD's 4000+ model). Reply
  • val - Thursday, March 03, 2005 - link

    I think that AMD have some PR meeting. We havent seen many nice products for some time so they plan some another forum spam burst or maybe some submarine advertising? Reply

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