By: David Kanter (dkanter.delete@this.realworldtech.com), February 8, 2015 12:39 am
Room: Moderated Discussions
Krait gets all this praise for being so power efficient but I have yet to see a real comparison with normalized
> performance on the same process and all that. All I've seen is comparisons where A15 uses more power (sometimes
> a lot more) while also performing better (sometimes a lot better).
Not on any vector workloads. The A15 had some terrible behavior when doing SIMD.
I repeat it constantly, but perf/W is
> not linear and these comparisons are meaningless. Reduce the clock speed on the A15 until it matches the
> performance on the Krait core and then do a fair measurement - of course, this will vary tremendously from
> benchmark to benchmark, especially since Krait appears to have some big glass jaws.
What do you think the glass jaws of Krait are?
> What we do know is this: despite your remarks that power management is "not so strong" in A57 Qualcomm
> still preferred to use it instead of a version of Krait that only added ARMv8 support, something
> I'm sure they could have done in time if it would have given them such an advantage.
I don't think so. I believe Qualcomm is only using ARM cores for their APs due to time to market constraints.
David
> performance on the same process and all that. All I've seen is comparisons where A15 uses more power (sometimes
> a lot more) while also performing better (sometimes a lot better).
Not on any vector workloads. The A15 had some terrible behavior when doing SIMD.
I repeat it constantly, but perf/W is
> not linear and these comparisons are meaningless. Reduce the clock speed on the A15 until it matches the
> performance on the Krait core and then do a fair measurement - of course, this will vary tremendously from
> benchmark to benchmark, especially since Krait appears to have some big glass jaws.
What do you think the glass jaws of Krait are?
> What we do know is this: despite your remarks that power management is "not so strong" in A57 Qualcomm
> still preferred to use it instead of a version of Krait that only added ARMv8 support, something
> I'm sure they could have done in time if it would have given them such an advantage.
I don't think so. I believe Qualcomm is only using ARM cores for their APs due to time to market constraints.
David
Topic | Posted By | Date |
---|---|---|
ARM announces A72 | Maynard Handley | 2015/02/03 11:36 AM |
ARM announces A72 | anon | 2015/02/03 12:53 PM |
ARM announces A72 | Hugo Décharnes | 2015/02/03 01:20 PM |
ARM announces A72 | juanrga | 2015/02/03 04:15 PM |
ARM announces A72 | Wilco | 2015/02/04 12:58 AM |
ARM announces A72 | Eric Bron | 2015/02/04 01:48 AM |
ARM announces A72 | none | 2015/02/04 02:24 AM |
ARM announces A72 | Eric Bron | 2015/02/04 02:42 AM |
ARM announces A72 | Exophase | 2015/02/04 07:01 AM |
ARM announces A72 | Anon | 2015/02/04 07:35 AM |
ARM announces A72 | Exophase | 2015/02/04 07:58 AM |
ARM announces A72 | Groo | 2015/02/04 09:24 AM |
ARM Marketing, BS up to my ears | David Kanter | 2015/02/04 10:51 AM |
ARM Marketing, BS up to my ears | Maynard Handley | 2015/02/04 01:59 PM |
ARM Marketing, BS up to my ears | David Kanter | 2015/02/04 02:21 PM |
ARM Marketing, BS up to my ears | Groo | 2015/02/04 02:30 PM |
ARM announces A72 | juanrga | 2015/02/04 04:23 AM |
ARM announces A72 | Wilco | 2015/02/04 03:01 PM |
ARM announces A72 | juanrga | 2015/02/04 04:06 PM |
ARM announces A72 | Anon | 2015/02/04 01:28 AM |
ARM announces A72 | juanrga | 2015/02/04 04:31 AM |
ARM announces A72 | Aaron Spink | 2015/02/04 06:49 AM |
ARM announces A72 | Ronald Maas | 2015/02/03 07:23 PM |
ARM announces A72 | Seni | 2015/02/04 12:19 AM |
ARM announces A72 | Maynard Handley | 2015/02/04 10:42 AM |
ARM announces A72 | Seni | 2015/02/04 12:33 PM |
ARM announces A72 | dmcq | 2015/02/04 12:57 PM |
ARM announces A72 | Ronald Maas | 2015/02/04 06:42 PM |
ARM announces A72 | anon | 2015/02/04 05:19 AM |
ARM announces A72 | Exophase | 2015/02/04 07:31 AM |
ARM announces A72 | David Kanter | 2015/02/04 10:25 AM |
ARM announces A72 | Exophase | 2015/02/04 01:33 PM |
ARM announces A72 | anon | 2015/02/04 10:27 PM |
ARM announces A72 (fixed format) | anon | 2015/02/04 10:29 PM |
ARM announces A72 | Exophase | 2015/02/04 11:11 PM |
ARM announces A72 | anon | 2015/02/05 12:02 AM |
ARM announces A72 | anon | 2015/02/04 05:57 PM |
ARM announces A72 | Wilco | 2015/02/03 01:39 PM |
ARM announces A72 | Maynard Handley | 2015/02/03 02:13 PM |
ARM announces A72 | anon | 2015/02/03 02:29 PM |
ARM announces A72 | Wilco | 2015/02/03 02:44 PM |
ARM announces A72 | David Kanter | 2015/02/04 09:56 AM |
ARM announces A72 | Peter Greenhalgh | 2015/02/04 10:56 AM |
ARM announces A72 | Aaron Spink | 2015/02/04 11:59 AM |
ARM announces A72 | Alberto | 2015/02/07 10:22 AM |
ARM announces A72 | Exophase | 2015/02/07 10:47 AM |
ARM announces A72 | Alberto | 2015/02/07 12:44 PM |
ARM announces A72 | Exophase | 2015/02/07 02:35 PM |
ARM announces A72 | Alberto | 2015/02/08 01:09 AM |
ARM announces A72 | Exophase | 2015/02/08 11:05 AM |
ARM announces A72 | David Kanter | 2015/02/08 12:39 AM |
ARM announces A72 | dmcq | 2015/02/08 04:14 AM |
ARM announces A72 | Michael S | 2015/02/08 04:38 AM |
ARM announces A72 | Gabriele Svelto | 2015/02/10 05:11 AM |
ARM announces A72 | Jouni Osmala | 2015/02/10 11:24 AM |
slit vs unified | Michael S | 2015/02/10 01:57 PM |
slit vs unified | dmcq | 2015/02/11 05:44 AM |
ARM announces A72 | Doug S | 2015/02/08 09:00 AM |
ARM announces A72 | Exophase | 2015/02/08 10:57 AM |
ARM announces A72 | dmcq | 2015/02/04 01:10 PM |
ARM announces A72 | David Kanter | 2015/02/04 02:28 PM |
ARM announces A72 | Wilco | 2015/02/04 01:59 PM |
ARM announces A72 | Aaron Spink | 2015/02/04 09:31 PM |
Intel 32nm vs 14 nm | Michael S | 2015/02/05 01:03 AM |
Intel 32nm vs 14 nm | Wilco | 2015/02/05 02:27 AM |
Intel 32nm vs 14 nm | David Kanter | 2015/02/05 09:05 AM |
Intel 32nm vs 14 nm | carop | 2015/02/05 11:12 AM |
Normalize to drawn or effective width? | David Kanter | 2015/02/05 11:45 AM |
Normalize to drawn or effective width? | carop | 2015/02/05 02:40 PM |
Normalize to drawn or effective width? | David Kanter | 2015/02/06 12:44 PM |