By: Wilco (Wilco.Dijkstra.delete@this.ntlworld.com), November 21, 2016 5:54 pm
Room: Moderated Discussions
juanrga (noemail.delete@this.juanrga.com) on November 20, 2016 5:56 am wrote:
> Wilco (Wilco.Dijkstra.delete@this.ntlworld.com) on November 14, 2016 3:53 pm wrote:
> > juanrga (noemail.delete@this.juanrga.com) on November 14, 2016 11:12 am wrote:
> > > Wilco (Wilco.Dijkstra.delete@this.ntlworld.com) on November 7, 2016 2:45 am wrote:
> > > > juanrga (noemail.delete@this.juanrga.com) on November 6, 2016 4:06 pm wrote:
> > > > >
> > > > > Now continue reading the reference until you get to the point where he discusses if Haswell
> > > > > would be considered 4-wide, 5-wide, or 8-wide, why it depends on what definition of "wide"
> > > > > you use,
> > > >
> > > > No the definition by itself is clear. Instructions are instructions, there
> > > > is no room for argument. No Intel core can decode/execute 8 instructions
> > > > per cycle. Apple A7 can do 6, Haswell can do 4, it's as simple as that.
> > >
> > > Same advice than before. Instead stop reading, continue reading the reference until you get to the
> > > point where he discusses if Haswell would be considered 4-wide, 5-wide, or 8-wide, why it depends
> > > on what definition of "wide" you use, and why he chose 8-wide, like I did, like many others do...
> >
> > When using his wrong definition, Apple A7 is 9 wide and Cortex-A72 8 wide.
> >
> > > > > and why he choses 8-wide (as myself did, as the other references given also did).
> > > >
> > > > The reason some people choose 8-wide is to pretend Intel's cores are wider than other
> > > > CPUs. When you look internally both Apple A7 and Cortex-A57 are wider than Haswell.
> > >
> > > I guess you must be kidding.
> >
> > Nope. This is a simple undeniable fact - you can verify by reading the links I
> > posted. That makes that guy's definition of width a bit dubious doesn't it?
> >
> > > > > The issue is that what you call "instructions" is not what is reordered, issued,
> > > > > executed, tracked, and retired in the metal of a modern chip as Haswell, or
> > > > > Cyclone, or A72, or Hurricane, or Zen, or Vulcan, or Kaby Lake, or...
> > > >
> > > > There is an almost 1:1 correspondence between instructions
> > > > and micro-ops, so yes instructions are what matters.
> > > >
> > >
> > > Not even in ARM that is true. Vulcan has a 1:(1.2) ratio between
> > > ARM instructions and muops. Denver has something like 1:(1.8).
> >
> > ARM quotes micro-op ratio of 1.08 for Cortex-A72, so yes that means ~95% of executed instructions
> > are a single micro-op. Denver isn't relevant here, and we don't have any details about Vulcan.
> >
> > Wilco
>
> The ratio of ARM instructions to uops can be 1.1, 1.2, or 1.8. It depends on the microarchitecture.
> Your claim there is almost 1:1 correspondence between instructions
> and uops is false and particularly wrong for x86.
There is a dependency on microarchitecture of course, but the ratio is typically very close to 1. And yes, that's true on x86 too - 1.03 on SPECINT and 1.07 on SPECFP.
Wilco
> Wilco (Wilco.Dijkstra.delete@this.ntlworld.com) on November 14, 2016 3:53 pm wrote:
> > juanrga (noemail.delete@this.juanrga.com) on November 14, 2016 11:12 am wrote:
> > > Wilco (Wilco.Dijkstra.delete@this.ntlworld.com) on November 7, 2016 2:45 am wrote:
> > > > juanrga (noemail.delete@this.juanrga.com) on November 6, 2016 4:06 pm wrote:
> > > > >
> > > > > Now continue reading the reference until you get to the point where he discusses if Haswell
> > > > > would be considered 4-wide, 5-wide, or 8-wide, why it depends on what definition of "wide"
> > > > > you use,
> > > >
> > > > No the definition by itself is clear. Instructions are instructions, there
> > > > is no room for argument. No Intel core can decode/execute 8 instructions
> > > > per cycle. Apple A7 can do 6, Haswell can do 4, it's as simple as that.
> > >
> > > Same advice than before. Instead stop reading, continue reading the reference until you get to the
> > > point where he discusses if Haswell would be considered 4-wide, 5-wide, or 8-wide, why it depends
> > > on what definition of "wide" you use, and why he chose 8-wide, like I did, like many others do...
> >
> > When using his wrong definition, Apple A7 is 9 wide and Cortex-A72 8 wide.
> >
> > > > > and why he choses 8-wide (as myself did, as the other references given also did).
> > > >
> > > > The reason some people choose 8-wide is to pretend Intel's cores are wider than other
> > > > CPUs. When you look internally both Apple A7 and Cortex-A57 are wider than Haswell.
> > >
> > > I guess you must be kidding.
> >
> > Nope. This is a simple undeniable fact - you can verify by reading the links I
> > posted. That makes that guy's definition of width a bit dubious doesn't it?
> >
> > > > > The issue is that what you call "instructions" is not what is reordered, issued,
> > > > > executed, tracked, and retired in the metal of a modern chip as Haswell, or
> > > > > Cyclone, or A72, or Hurricane, or Zen, or Vulcan, or Kaby Lake, or...
> > > >
> > > > There is an almost 1:1 correspondence between instructions
> > > > and micro-ops, so yes instructions are what matters.
> > > >
> > >
> > > Not even in ARM that is true. Vulcan has a 1:(1.2) ratio between
> > > ARM instructions and muops. Denver has something like 1:(1.8).
> >
> > ARM quotes micro-op ratio of 1.08 for Cortex-A72, so yes that means ~95% of executed instructions
> > are a single micro-op. Denver isn't relevant here, and we don't have any details about Vulcan.
> >
> > Wilco
>
> The ratio of ARM instructions to uops can be 1.1, 1.2, or 1.8. It depends on the microarchitecture.
> Your claim there is almost 1:1 correspondence between instructions
> and uops is false and particularly wrong for x86.
There is a dependency on microarchitecture of course, but the ratio is typically very close to 1. And yes, that's true on x86 too - 1.03 on SPECINT and 1.07 on SPECFP.
Wilco
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 |