By: juanrga (noemail.delete@this.juanrga.com), November 4, 2016 5:05 am
Room: Moderated Discussions
anon (spam.delete.delete@this.this.spam.com) on November 4, 2016 3:38 am wrote:
> juanrga (noemail.delete@this.juanrga.com) on November 3, 2016 12:35 pm wrote:
> > anon (spam.delete.delete@this.this.spam.com) on November 1, 2016 1:00 pm wrote:
> > > juanrga (noemail.delete@this.juanrga.com) on October 31, 2016 4:55 am wrote:
> > > > Travis (travis.downs.delete@this.gmail.com) on October 30, 2016 7:13 pm wrote:
> > > > > juanrga (noemail.delete@this.juanrga.com) on October 30, 2016 2:56 pm wrote:
> > > > > > Indeed and if the core stalls would it be considered 0-wide? Evidently, there is two ways to define
> > > > > > the wide, either as a kind of average, which is not very useful because it depends on the elements
> > > > > > of the ensemble taken to compute the average or we define wide as the maximum allowed by the architecture.
> > > > > > Thus even if Broadwell cannot sustain 8 uops per cycle, we define it as 8-wide.
> > > > > >
> > > > > > It is also useful to mention context; we were trying to
> > > > > > explain the reasons why Broadwell core is much bigger
> > > > > > than Hurricane core. Even if Broadwell cannot sustain 8
> > > > > > uops, it has all the circuitry and transistors needed
> > > > > > to issue "up to" 8 uops, and that adds to the size of the core compared to a 6-wide Hurricane.
> > > > >
> > > > > No it is not "evident" that those are the only two ways to define it, and the one you chose is
> > > > > totally impractical and not one I've ever heard use.
> > > >
> > > > You would open your hears then, because I am not the first
> > > > to claim that Haswell is 8-wide and Cyclone is 6-wide.
> > > >
> > > > http://www.lighterra.com/papers/modernmicroprocessors/#multipleissuesuperscalar
> > > >
> > > >
> > > >
> > > > https://hal.inria.fr/hal-01193178/document
> > > >
> > > > And so on...
> > >
> > > Don't use VISC marketing. Please. It's such a trainwreck.
> > > Remember this? http://images.anandtech.com/doci/10025/Presentation%20%2810%29.jpg
> > >
> > > I mean I respect what they are doing and I'm pretty sure they know
> > > what they're doing, but their marketing department? God no.
> >
> > (i)
> > I have given three resources. Those aren't all that exist, but are three easy to find online and link here.
> >
> > (ii)
> > I know Soft Machines marketing. I have criticized their marketing claims about VISC in
> > threads available in this site. I wasn't quoting that kind of marketing, but only the
> > slide reporting the wides of different available cores made by other companies. Their
> > claims about the wide of different cores agree with the other resources provided.
>
> Ok, let's say your 1st and 2nd source are right. Didn't find anything
> interesting in the 3rd, maybe you could point me to a page.
First page:
> So the A7/A8 is 6 wide, Haswell/Broadwell are 8 wide.
>
> Now you need to explain why that means that the A10 is still
> 6 wide even though it got significantly higher IPC.
IPC depends on the issue width (and in other microarchitectural elements) through a series of parameters [1] that depend on both microarchitecture details and the program being executed.
Two designs can be both 6-wide and one be significantly faster than other clock-for-clock, due to having better parameters (for instance more accurate branch prediction hardware).
[1] L1 i-cache misses, branch mispredictions, nonoverlapping long d-cache L2 misses, latch overhead, pipeline depth,...
> juanrga (noemail.delete@this.juanrga.com) on November 3, 2016 12:35 pm wrote:
> > anon (spam.delete.delete@this.this.spam.com) on November 1, 2016 1:00 pm wrote:
> > > juanrga (noemail.delete@this.juanrga.com) on October 31, 2016 4:55 am wrote:
> > > > Travis (travis.downs.delete@this.gmail.com) on October 30, 2016 7:13 pm wrote:
> > > > > juanrga (noemail.delete@this.juanrga.com) on October 30, 2016 2:56 pm wrote:
> > > > > > Indeed and if the core stalls would it be considered 0-wide? Evidently, there is two ways to define
> > > > > > the wide, either as a kind of average, which is not very useful because it depends on the elements
> > > > > > of the ensemble taken to compute the average or we define wide as the maximum allowed by the architecture.
> > > > > > Thus even if Broadwell cannot sustain 8 uops per cycle, we define it as 8-wide.
> > > > > >
> > > > > > It is also useful to mention context; we were trying to
> > > > > > explain the reasons why Broadwell core is much bigger
> > > > > > than Hurricane core. Even if Broadwell cannot sustain 8
> > > > > > uops, it has all the circuitry and transistors needed
> > > > > > to issue "up to" 8 uops, and that adds to the size of the core compared to a 6-wide Hurricane.
> > > > >
> > > > > No it is not "evident" that those are the only two ways to define it, and the one you chose is
> > > > > totally impractical and not one I've ever heard use.
> > > >
> > > > You would open your hears then, because I am not the first
> > > > to claim that Haswell is 8-wide and Cyclone is 6-wide.
> > > >
> > > > http://www.lighterra.com/papers/modernmicroprocessors/#multipleissuesuperscalar
> > > >
> > > >

> > > >
> > > > https://hal.inria.fr/hal-01193178/document
> > > >
> > > > And so on...
> > >
> > > Don't use VISC marketing. Please. It's such a trainwreck.
> > > Remember this? http://images.anandtech.com/doci/10025/Presentation%20%2810%29.jpg
> > >
> > > I mean I respect what they are doing and I'm pretty sure they know
> > > what they're doing, but their marketing department? God no.
> >
> > (i)
> > I have given three resources. Those aren't all that exist, but are three easy to find online and link here.
> >
> > (ii)
> > I know Soft Machines marketing. I have criticized their marketing claims about VISC in
> > threads available in this site. I wasn't quoting that kind of marketing, but only the
> > slide reporting the wides of different available cores made by other companies. Their
> > claims about the wide of different cores agree with the other resources provided.
>
> Ok, let's say your 1st and 2nd source are right. Didn't find anything
> interesting in the 3rd, maybe you could point me to a page.
First page:
[...] while the more recent Intel Haswell microarchitecture can issue 8 micro-ops per cycle from a 60-entry issue buffer [Intel 2014].
> So the A7/A8 is 6 wide, Haswell/Broadwell are 8 wide.
>
> Now you need to explain why that means that the A10 is still
> 6 wide even though it got significantly higher IPC.
IPC depends on the issue width (and in other microarchitectural elements) through a series of parameters [1] that depend on both microarchitecture details and the program being executed.
Two designs can be both 6-wide and one be significantly faster than other clock-for-clock, due to having better parameters (for instance more accurate branch prediction hardware).
[1] L1 i-cache misses, branch mispredictions, nonoverlapping long d-cache L2 misses, latch overhead, pipeline depth,...
Topic | Posted By | Date |
---|---|---|
Neat die area comparison image | Rob | 2016/10/21 05:39 PM |
Neat die area comparison image | anonymou5 | 2016/10/21 06:44 PM |
Neat die area comparison image | Mr. Camel | 2016/10/22 04:58 AM |
Neat die area comparison image | Heikki Kultala | 2016/10/22 05:19 AM |
Neat die area comparison image | Mr. Camel | 2016/10/22 07:10 AM |
Neat die area comparison image | Mr. Camel | 2016/10/22 07:15 AM |
different caches... | Heikki Kultala | 2016/10/22 08:29 AM |
Broadwell includes LLC, just for comparision | anon | 2016/10/22 08:52 AM |
Broadwell includes LLC, just for comparision | juanrga | 2016/10/23 06:09 AM |
Broadwell includes LLC, just for comparision | anon | 2016/10/23 07:25 AM |
Broadwell includes LLC, just for comparision | juanrga | 2016/10/25 09:57 AM |
Broadwell includes LLC, just for comparision | Simon Farnsworth | 2016/10/25 11:03 AM |
Broadwell includes LLC, just for comparision | juanrga | 2016/10/28 02:02 AM |
Broadwell includes LLC, just for comparision | anon | 2016/10/28 04:13 AM |
Broadwell includes LLC, just for comparision | juanrga | 2016/10/29 09:47 PM |
Broadwell includes LLC, just for comparision | Travis | 2016/10/30 06:34 PM |
Broadwell includes LLC, just for comparision | juanrga | 2016/10/31 04:35 AM |
Broadwell includes LLC, just for comparision | Simon Farnsworth | 2016/10/31 04:42 AM |
Broadwell includes LLC, just for comparision | anon | 2016/11/01 12:56 PM |
Broadwell includes LLC, just for comparision | Maynard Handley | 2016/11/01 01:37 PM |
Broadwell includes LLC, just for comparision | anon | 2016/11/01 04:22 PM |
Broadwell includes LLC, just for comparision | Maynard Handley | 2016/11/01 07:30 PM |
Broadwell includes LLC, just for comparision | anon | 2016/11/02 06:15 AM |
Broadwell includes LLC, just for comparision | Maynard Handley | 2016/11/02 09:23 AM |
Broadwell includes LLC, just for comparision | anon | 2016/11/02 11:50 AM |
Broadwell includes LLC, just for comparision | Simon Farnsworth | 2016/11/02 02:48 AM |
Broadwell includes LLC, just for comparision | Simon Farnsworth | 2016/10/28 06:19 AM |
Broadwell includes LLC, just for comparision | juanrga | 2016/10/29 10:15 PM |
Broadwell includes LLC, just for comparision | Simon Farnsworth | 2016/10/30 12:31 PM |
Broadwell includes LLC, just for comparision | Ricardo B | 2016/10/29 05:30 PM |
underclocked is different than designed for low clock speed | Heikki Kultala | 2016/10/25 11:47 PM |
underclocked is different than designed for low clock speed | Maynard Handley | 2016/10/26 10:07 AM |
That wasn't the point | juanrga | 2016/10/28 02:15 AM |
Even without the point you have invalid comparison | Heikki Kultala | 2016/10/28 09:03 AM |
8 wide vs 6 wide | juanrga | 2016/10/29 10:41 PM |
8 wide vs 6 wide | Wilco | 2016/10/30 05:00 AM |
8 wide vs 6 wide | Doug S | 2016/10/30 12:20 PM |
8 wide vs 6 wide | Wilco | 2016/10/30 01:12 PM |
8 wide vs 6 wide | juanrga | 2016/10/30 02:56 PM |
8 wide vs 6 wide | Travis | 2016/10/30 07:13 PM |
8 wide vs 6 wide | juanrga | 2016/10/31 04:55 AM |
8 wide vs 6 wide | anon | 2016/11/01 01:00 PM |
SoftMachines | none | 2016/11/02 03:57 AM |
SoftMachines | David Kanter | 2016/11/02 08:53 AM |
8 wide vs 6 wide | juanrga | 2016/11/03 12:35 PM |
8 wide vs 6 wide | Wilco | 2016/11/03 02:13 PM |
8 wide vs 6 wide | juanrga | 2016/11/03 07:35 PM |
8 wide vs 6 wide | Wilco | 2016/11/04 01:27 PM |
8 wide vs 6 wide | juanrga | 2016/11/04 06:08 PM |
8 wide vs 6 wide | Wilco | 2016/11/06 04:52 AM |
8 wide vs 6 wide | juanrga | 2016/11/06 04:56 PM |
8 wide vs 6 wide | Wilco | 2016/11/07 04:25 AM |
8 wide vs 6 wide | Aaron Spink | 2016/11/04 04:08 PM |
8 wide vs 6 wide | juanrga | 2016/11/04 06:10 PM |
Dunning-Krueger effect | Heikki Kultala | 2016/11/04 03:22 AM |
Dunning-Krueger effect | itsmydamnation | 2016/11/04 02:48 PM |
8 wide vs 6 wide | anon | 2016/11/04 03:38 AM |
8 wide vs 6 wide | juanrga | 2016/11/04 05:05 AM |
8 wide vs 6 wide | anon | 2016/11/04 06:12 AM |
8 wide vs 6 wide | Wilco | 2016/11/04 01:12 PM |
8 wide vs 6 wide | anon | 2016/11/04 02:54 PM |
8 wide vs 6 wide | juanrga | 2016/11/04 05:34 PM |
8 wide vs 6 wide | anon | 2016/11/05 02:14 AM |
8 wide vs 6 wide | juanrga | 2016/11/04 05:39 PM |
8 wide vs 6 wide | Wilco | 2016/11/06 05:15 AM |
8 wide vs 6 wide | juanrga | 2016/11/06 05:06 PM |
8 wide vs 6 wide | Wilco | 2016/11/07 03:45 AM |
8 wide vs 6 wide | David Kanter | 2016/11/07 08:43 PM |
8 wide vs 6 wide | Wilco | 2016/11/08 03:57 AM |
8 wide vs 6 wide | juanrga | 2016/11/14 12:12 PM |
8 wide vs 6 wide | Wilco | 2016/11/14 04:53 PM |
8 wide vs 6 wide | dmcq | 2016/11/15 03:17 AM |
8 wide vs 6 wide | Wilco | 2016/11/15 03:43 AM |
8 wide vs 6 wide | dmcq | 2016/11/15 04:28 AM |
1 µop per instruction is not necessary | Paul A. Clayton | 2016/11/17 12:09 PM |
8 wide vs 6 wide | juanrga | 2016/11/20 06:56 AM |
8 wide vs 6 wide | Wilco | 2016/11/21 05:54 PM |
8 wide vs 6 wide | juanrga | 2016/11/22 08:49 AM |
8 wide vs 6 wide | Wilco | 2016/11/22 03:25 PM |
8 wide vs 6 wide | Wilco | 2016/10/31 03:03 AM |
Skylake can retire 8 uops | David Kanter | 2016/10/31 12:41 AM |
Skylake can retire 8 uops | juanrga | 2016/10/31 04:15 AM |
Skylake can retire 8 uops | Alberto | 2016/11/04 07:22 AM |
8 wide vs 6 wide bogus numbers | Heikki Kultala | 2016/10/30 06:25 AM |
Broadwell includes LLC, just for comparision | anon | 2016/10/26 03:10 AM |
Pushing the hidden agenda | juanrga | 2016/10/28 03:11 AM |
Pushing the hidden agenda | anon | 2016/10/28 04:35 AM |
Neat die area comparison image | David Hess | 2016/10/22 01:26 PM |
Neat die area comparison image | anon2 | 2016/10/22 05:20 PM |
Neat die area comparison image | David Hess | 2016/10/22 10:31 PM |
Neat die area comparison image | anon2 | 2016/10/23 01:50 AM |
Neat die area comparison image | Travis | 2016/10/24 01:26 PM |
Neat die area comparison image | Maynard Handley | 2016/10/24 04:27 PM |
Neat die area comparison image | juanrga | 2016/10/25 10:02 AM |
Neat die area comparison image | David Hess | 2016/10/25 09:59 PM |
Neat die area comparison image | Travis | 2016/10/25 10:22 PM |
Neat die area comparison image | David Hess | 2016/10/25 10:37 PM |
Neat die area comparison image | Travis | 2016/10/30 06:09 PM |
Neat die area comparison image | Gabriele Svelto | 2016/10/26 02:23 AM |
Neat die area comparison image | Doug S | 2016/10/26 08:17 AM |
Neat die area comparison image | Jukka Larja | 2016/10/27 09:28 AM |
Neat die area comparison image | anon | 2016/10/26 03:32 AM |
Neat die area comparison image | juanrga | 2016/10/23 06:29 AM |
Neat die area comparison image | Matthias Waldhauer | 2016/10/22 06:12 AM |
Neat die area comparison image | juanrga | 2016/10/23 05:44 AM |
Neat die area comparison image | Gabriele Svelto | 2016/10/24 02:17 AM |