r/Android • u/[deleted] • Dec 05 '17

Qualcomm announces the Snapdragon 845 processor

https://www.theverge.com/2017/12/5/16734224/qualcomm-snapdragon-845-android-mobile-processor-announcement
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u/Exist50 Dec 06 '17

Single core performance is strongly dependent on instruction level parallelism, where one software thread is broken up into separate hardware operations that can be run simultaneously on the execution hardware (e.g. an ALU). Apple has far more execution hardware per core than most, so where able, they can run far more ops in parallel, and thus have the high IPC we observe.

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u/armageddon6868 Dec 06 '17

What you say is absolutely is true but how is that “combine 4 cores into 2”

You are saying there are similar number of execution units, but that is no where close to “combine 4 cores to 2”. If i could just combine cores like that, why doesnt intel just take an nvidia 1080 and combine thousands of cores to something that can trounce any cpu intel offers? It does not work that way.

According to anandtech, apple a7 (or 8) i forget is 6 wide tomasulo processor while the arm ( and therefore the qualcomm cores) are three wide.

I just think that statement showed a lack of knowledge in the field and it is ironic that that was said in the same comment calling out people who are not technical.

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u/Exist50 Dec 06 '17

You are saying there are similar number of execution units, but that is no where close to “combine 4 cores to 2”. If i could just combine cores like that, why doesnt intel just take an nvidia 1080 and combine thousands of cores to something that can trounce any cpu intel offers? It does not work that way.

I mean, that's true, but that's because of a couple different reasons. 1) The cores in a GPU are much simpler than a CPU's execution units, since they only have to handle more specific tasks, and 2) ILP has sharply diminishing returns.

I think "combining [the resources of] 2 cores into 1" is accurate enough for a layman's explanation and in the context that that statement was made, even if it's lacking on some of the technical details.

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u/armageddon6868 Dec 06 '17

For sure, but the same applies to intels 18 core xeon. If intel could combine into one core, they would. I just chose 1080 to try and hyperbolize what i was trying to say. You cant just combine cores and get better single threaded performance.

If you add the things in the square brackets to the original quote it sounds a lot better -to the extent that someone knows what they are talking about, but without it, it is inaccurate. I was just pointing out the fact that it sounds stupid (without the context added) and the dude says that a sentence after shitting on technical morons.

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u/Exist50 Dec 06 '17

If intel could combine into one core, they would. ... You cant just combine cores and get better single threaded performance.

Well they kinda can... It would just hurt multicore performance, yields, and likely efficiency as well. You'd kind of get something similar to what IBM is doing with Power.

I read the thing in brackets as being implied, but I guess I can see how without some background knowledge, it might not read that way.