By: dess (dess.delete@this.nospam.com), May 22, 2007 5:52 am
Room: Moderated Discussions
Gipsel (abc@def.com) on 5/22/07 wrote:
---------------------------
>Intel changed more or less their definition of a µOp with the introduction of the
>PentiumM (later renamed to core, the ones which incorporate µOp fusion). They don't
>differentiate between fused µOps and not fused ones. When looking at the possible
>µOps fused together you really get the impression that intel more or less adopted
>AMDs concept of MacroOps consisting of an ALU µOp and and load-store µOp. Both (fused
>µOps and MacroOps) get split up in two individual µOps later in the pipeline. Agner
>is absolutely right that they are more or less equivalent.
I just wonder how often such a fusion is happening, while it seems a macro-op is holding two micro-ops (an integer/fp operation, and a load/store/load-store one) most of the time.
>But I don't think Core2 is really that much wider than Barcelona. First you have
>to consider that Core 2 has more restrictions to its 4 decoders (only one complex
>one, smaller fetch bandwidth and smaller predecode buffer). It's clear that core2
>is not able to sustain a higher decode rate than Barcelona on all workloads.
I did exactly this in some of my earlier posts in this thread.
> Additionally
>the core2 has a six issue execution core, but only three issue ports can accept
>arithmetical instruction. The other three issue ports only accepts memory operations.
>That means the peak execution rate is also not necessarily higher on core2 than
>on K8/Barcelona. But the 4µOp execution rate of the Core2 will help if you have
>some "RISCy" x86 code, that means separate load instruction followed by register
>operations instead of load-use operations (but core2 should still prefer one load-use operation over two separate ones).
>
>>(BTW, Agner is using micro-op all along, also on Intel's CPUs, instead of uop. uop
>>is perhaps just a witty abbrevation, isn't it?)
>
>Exactly. Actually it isn't uOp, it's µOp. As you know, "µ" is the greek letter
>"micro". Most keyboards simply lack a key for that letter.
Of course, but there is no µ on my keyboard. :) It's common to use a u instead of µ.
---------------------------
>Intel changed more or less their definition of a µOp with the introduction of the
>PentiumM (later renamed to core, the ones which incorporate µOp fusion). They don't
>differentiate between fused µOps and not fused ones. When looking at the possible
>µOps fused together you really get the impression that intel more or less adopted
>AMDs concept of MacroOps consisting of an ALU µOp and and load-store µOp. Both (fused
>µOps and MacroOps) get split up in two individual µOps later in the pipeline. Agner
>is absolutely right that they are more or less equivalent.
I just wonder how often such a fusion is happening, while it seems a macro-op is holding two micro-ops (an integer/fp operation, and a load/store/load-store one) most of the time.
>But I don't think Core2 is really that much wider than Barcelona. First you have
>to consider that Core 2 has more restrictions to its 4 decoders (only one complex
>one, smaller fetch bandwidth and smaller predecode buffer). It's clear that core2
>is not able to sustain a higher decode rate than Barcelona on all workloads.
I did exactly this in some of my earlier posts in this thread.
> Additionally
>the core2 has a six issue execution core, but only three issue ports can accept
>arithmetical instruction. The other three issue ports only accepts memory operations.
>That means the peak execution rate is also not necessarily higher on core2 than
>on K8/Barcelona. But the 4µOp execution rate of the Core2 will help if you have
>some "RISCy" x86 code, that means separate load instruction followed by register
>operations instead of load-use operations (but core2 should still prefer one load-use operation over two separate ones).
>
>>(BTW, Agner is using micro-op all along, also on Intel's CPUs, instead of uop. uop
>>is perhaps just a witty abbrevation, isn't it?)
>
>Exactly. Actually it isn't uOp, it's µOp. As you know, "µ" is the greek letter
>"micro". Most keyboards simply lack a key for that letter.
Of course, but there is no µ on my keyboard. :) It's common to use a u instead of µ.
Topic | Posted By | Date |
---|---|---|
Barcelona Article Online | David Kanter | 2007/05/16 03:20 AM |
Barcelona Article Online | PiedPiper | 2007/05/16 05:12 AM |
Yes, I left out a sentence there. Fixed (NT) | David Kanter | 2007/05/16 12:07 PM |
Barcelona Article Online | anonymous | 2007/05/16 06:01 AM |
Barcelona Article Online | Anonymous | 2007/05/16 06:28 PM |
Barcelona Article Online | anonymous | 2007/05/16 07:52 PM |
Barcelona Article Online | Anonymous1 | 2007/05/16 07:08 AM |
Barcelona Article Online | Dean M | 2007/05/16 11:09 AM |
Barcelona Article Online | David Kanter | 2007/05/16 12:38 PM |
Barcelona Article Online | Dean M | 2007/05/16 02:10 PM |
Barcelona Article Online | IntelUser2000 | 2007/05/16 02:59 PM |
Barcelona Article Online | Linus Torvalds | 2007/05/16 03:24 PM |
Barcelona Article Online | David Kanter | 2007/05/16 04:57 PM |
Barcelona Article Online | Michael S | 2007/05/17 05:07 AM |
Barcelona Article Online | IntelUser2000 | 2007/05/18 08:58 PM |
8 socket servers | Doug Siebert | 2007/05/16 04:58 PM |
8 socket servers | Michael S | 2007/05/17 05:20 AM |
8 socket servers | Joe Chang | 2007/05/17 07:38 AM |
8 socket servers | Alex Jones | 2007/05/17 09:35 AM |
8 socket servers | Jose | 2007/05/23 08:23 AM |
8 socket servers | Michael S | 2007/05/23 11:37 AM |
8 socket servers | anonymous | 2007/05/26 03:49 PM |
8 socket servers | Joe Chang | 2007/05/27 01:46 PM |
8 socket servers | Doug Siebert | 2007/05/23 09:56 PM |
8 socket servers | Joe Chang | 2007/05/24 04:33 AM |
8 socket servers | Anonymous | 2007/05/24 11:18 AM |
8 socket servers | Doug Siebert | 2007/05/24 10:47 PM |
8 socket servers | Linus Torvalds | 2007/05/25 10:35 AM |
8 socket servers | Nick | 2007/05/25 02:29 AM |
Performance estimation seems odd | Hotar | 2007/05/17 01:54 AM |
Performance estimation seems odd | David Kanter | 2007/05/17 08:38 AM |
microops vs macroops on page 4 | Peter Lund | 2007/05/17 12:04 PM |
microops vs macroops on page 4 | David Kanter | 2007/05/21 04:51 PM |
microops vs macroops on page 4 | EduardoS | 2007/05/21 05:42 PM |
microops vs macroops on page 4 | dess | 2007/05/21 07:00 PM |
Barcelona Article Online | Peter Lund | 2007/05/17 12:25 PM |
macro-op vs. micro-op | dess | 2007/05/21 07:24 AM |
macro-op vs. micro-op | David Kanter | 2007/05/21 04:38 PM |
macro-op vs. micro-op | dess | 2007/05/21 06:15 PM |
macro-op vs. micro-op | David Kanter | 2007/05/22 12:11 AM |
macro-op vs. micro-op | dess | 2007/05/22 03:56 AM |
macro-op vs. micro-op | Gipsel | 2007/05/22 05:05 AM |
macro-op vs. micro-op | dess | 2007/05/22 05:52 AM |
macro-op vs. micro-op | anonymous | 2007/05/22 06:14 AM |
macro-op vs. micro-op | dess | 2007/05/22 06:44 AM |
macro-op vs. micro-op | EduardoS | 2007/05/22 02:19 PM |
macro-op vs. micro-op | dess | 2007/05/24 08:52 AM |
Stop comparing apples to oranges | EduardoS | 2007/05/22 02:30 PM |
Stop comparing apples to oranges | dess | 2007/05/22 04:09 PM |
Stop comparing apples to oranges | dess | 2007/05/22 04:30 PM |
Stop comparing apples to oranges | EduardoS | 2007/05/22 04:31 PM |
Stop comparing... apples to oranges? | dess | 2007/05/24 09:30 AM |
Stop comparing apples to oranges | anonymous | 2007/05/22 08:12 PM |
Stop comparing apples to oranges | EduardoS | 2007/05/23 02:50 PM |
macro-op vs. micro-op | anonymous | 2007/05/22 06:08 AM |
macro-op vs. micro-op | dess | 2007/05/22 06:40 AM |
macro-op vs. micro-op | anonymous | 2007/05/22 06:48 AM |
macro-op vs. micro-op | dess | 2007/05/21 08:30 PM |
macro-op vs. micro-op | anonymous | 2007/05/22 06:44 AM |
macro-op vs. micro-op | dess | 2007/05/24 09:38 AM |
macro-op vs. micro-op | Michael S | 2007/05/22 05:26 AM |