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Sometimes performance is not the main factor

Sometimes performance is not the main factor

Posted Oct 22, 2009 0:18 UTC (Thu) by nix (subscriber, #2304)
In reply to: Sometimes performance is not the main factor by ncm
Parent article: KS2009: Performance regressions

The speed of processors is increasing?

Their *parallelism* is increasing, but where I live the speed increases
topped out four or five years back.

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Sometimes performance is not the main factor

Posted Oct 22, 2009 11:02 UTC (Thu) by djcapelis (subscriber, #53964) [Link]

It's important to remember that just because clock speed isn't increasing at a large rate anymore doesn't mean the micro-architectures are standing still, even at a single-core level. Some of the improvements in the core microarchitecture over say... the P4 microarchitecture are welcome and should yield performance improvements.

That said, I would agree in general that single-core performance is not indeed climbing as much as it used to be, but to say it's completely standing still probably goes too far.

Even the clock speeds on consumer chips may still have room to improve. IBM was surprised to see everyone stop at 3Ghz which is why they turned that crank one last time to hit 5Ghz in POWER. They mostly did it for marketing purposes, but in terms of long-term trends, they seem to feel that that's the place clockspeeds top out. Not where we are now.

That said, none of this refutes your point really, but perhaps provides some different color to it.

Sometimes performance is not the main factor

Posted Oct 22, 2009 16:43 UTC (Thu) by dlang (subscriber, #313) [Link]

when you talk about how the micro architecture has improved since the P4, you also need to look a little futher back because the P4 was a huge step backwards in terms of micro architecture efficiancy (they went for lock speed instead)

Sometimes performance is not the main factor

Posted Oct 23, 2009 0:11 UTC (Fri) by djcapelis (subscriber, #53964) [Link]

Yes, the P4 was a step backwards in terms of microarchitecture. But as I said, now that the ghz wars are over, people are working on improving microarchitectures and that's where performance improvement is focused.

Even if the only thing they were doing was rolling back the P4's braindead design decisions, this would still be true.

That said, this isn't the only thing they're doing and the new Core microarchitectures are really quite an improvement over anything Intel's ever done before. I'm not thrilled with the original Core, but Core 2 on has been an improvement.

I'm not saying it's great, clearly Intel's never going to do cutting edge radical microarchitectures like Tilera, Sun or even IBM (from more radical to least) but you can't possibly claim their newer microarchitectures aren't an improvement that offer tangible benefits to single-core performance.

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