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Subject: Re: Is SPEC a bad test organisation according to Hyatt?

Author: Vincent Diepeveen

Date: 15:05:55 03/01/04

Go up one level in this thread


On March 01, 2004 at 17:16:36, Matthew Hull wrote:

>On March 01, 2004 at 16:53:51, Gerd Isenberg wrote:
>
>>On March 01, 2004 at 16:24:16, Robert Hyatt wrote:
>>
>>>On March 01, 2004 at 15:15:11, Vincent Diepeveen wrote:
>>>
>>>>On March 01, 2004 at 14:24:50, Robert Hyatt wrote:
>>>>
>>>>>On March 01, 2004 at 14:20:41, Robert Hyatt wrote:
>>>>>
>>>>>>On March 01, 2004 at 13:59:25, Eugene Nalimov wrote:
>>>>>>
>>>>>>>On March 01, 2004 at 13:49:38, Eugene Nalimov wrote:
>>>>>>>
>>>>>>>>On March 01, 2004 at 12:05:17, Vincent Diepeveen wrote:
>>>>>>>>
>>>>>>>>>On February 29, 2004 at 23:38:31, Robert Hyatt wrote:
>>>>>>>>>
>>>>>>>>>[snip]
>>>>>>>>>
>>>>>>>>>You qualify the testresults as done for SPEC as INVALID and INCORRECT?
>>>>>>>>>
>>>>>>>>>YES or NO?
>>>>>>>>>
>>>>>>>>>[bla bla removed]
>>>>>>>>
>>>>>>>>Had you stopped to drink vodka every morning?
>>>>>>>>
>>>>>>>>Please answer only YES or NO.
>>>>>>>>
>>>>>>>>[bla bla removed]
>>>>>>>
>>>>>>>So, my previous post pointed that there are questions for which you cannot
>>>>>>>answer "YES or NO".
>>>>>>>
>>>>>>>And here is *official* SPEC data for 1.3GHz K7 and 1.5GHz Itanium2:
>>>>>>>
>>>>>>>http://www.spec.org/cpu2000/results/res2001q4/cpu2000-20011008-01018.html
>>>>>>>http://www.spec.org/cpu2000/results/res2004q1/cpu2000-20040126-02775.html
>>>>>>>
>>>>>>>Thanks,
>>>>>>>Eugene
>>>>>>
>>>>>>
>>>>>>Please do not confuse discussions with Vincent by supplying real data.  Things
>>>>>>stay on a more equal footing if you just make up stuff and post it here.
>>>>>>
>>>>>><sarcasm off>
>>>>>>
>>>>>>:)
>>>>>
>>>>>
>>>>>For those that didn't look at the data, the 1.5ghz K7 compared to the 1.5ghz
>>>>>itanium shows a 50% faster speed on the Itanium.  IE the K7 took 127 seconds to
>>>>>run the test, the Itanium took 80.
>>>>>
>>>>>Why 1.5ghz K7?  Because Vincent was talking about "clock for clock" and Eugene
>>>>>chose to supply real data rather than barking up a hollow tree...
>>>>
>>>>Latest itanium compiler 1.5Ghz 6MB L3. Compiler used from 2004.
>>>>    base score : 1241
>>>>Note this is the HP compiler which hardly anyone uses. No one in government is.
>>>>They all use the way slower intel compiler. The supercomputers of the government
>>>>aren't HP ones. HP isn't delivering big enough systems.
>>>>
>>>>But even then. Let's compare this 6 instructions a cycle Itanium2 with crafty at
>>>>K7 a 32 bits doing 3 instructions a cycle max:
>>>
>>>Flap flap flap flap.  Flappety flap.  Flap.  Flap.  flap-flap-flap.
>>>
>>>No matter how much hand-flapping you do, you made the original statement.
>>>Eugene supplied data that showed that clock for clock, the Itanium was 50%
>>>faster with Crafty.  Nothing more, nothing less.  No flappety-flap either.
>>>
>>>
>>>
>>>
>>>
>>>>
>>>>http://www.spec.org/osg/cpu2000/results/res2003q2/cpu2000-20030505-02154.html
>>>>K7 at 2.2Ghz getting: 1324
>>>>
>>>>So after concluding that itanium is hell of a lot slower than K7, we can look to
>>>>the IPC.
>>>
>>>
>>>flappety-flap.
>>>
>>>Who cares.  You said something that was simply shown to be wrong.
>>>
>>>
>>>>
>>>>The 6 instructions a clock from the itanium2 @ 64 bits delivers :
>>>>  1241/1324 * 2.2Ghz/1.5Ghz = 37% faster speed
>>>>
>>>>So years of work at compiler still didn't improve much from my 33% statement
>>>>that the 4 instructions a clock 21264 1Ghz delivered a few years ago.
>>>>
>>>>So the move from 32 bits to 64 bits can not have contributed more than a few %
>>>>of speed to crafty.
>>>>
>>>>Best regards,
>>>>Vincent
>>>
>>>"can not have contributed -> flappety flap."
>>>
>>>One of these days, I will have access to an opteron where I can do a 32 bit and
>>>64 bit compile with _everything_ else constant.  Then we will _really_ know what
>>>32 -> 64 bit gives.  It will be more than "a few %".
>>
>>I'll hope it ;-)
>>
>>OTOH how do you distinguish the gain of using additional registers even for
>>32-bit ints, which may dramatically decrease stack bandwidth and the gain of
>>pure 64-bit processing.
>
>
>Other 32-bit architectures (PPC) with plenty of registers do not show dramatic
>difference over x86-32 at the same clock speed (I know, apples/oranges :)).
>However, somebody posted G3/G5 numbers not too long ago which seemed to indicate
>64 bit improvment over 32-bit was very good on PPC.......IIRC.

That apple show was the show of a fool.

If i remember well they first compiled with GCC at x86 hardware a few
benchmarks.

Then they compared that with gcc at the G5.

Real sick compare.

So all we know it's a slow CPU, that's all. How slow is not clear simply.

>
>>Do you have an idea, by profiling or estimation, of the
>>ratio between the number of average executed 32-bit and 64-bit instructions
>>inside crafty's search and eval?
>>
>>With some dependent bitboard operations you may introduce more register stalls
>>and probably less densitity using all execution ressources in parallel within
>>one processor, where 32-bit could do two independent instructions in parallel.
>>(intel64 with HT is coming ;-)
>>
>>With shifts, specially with generalized, there is really a huge win. But with
>>store/load and simple logical/arithmetical instructions and bitscan the win
>>isn't that huge, considering sequentially preparing and traversing one single
>>bitboard inside a register.
>>
>>Cheers,
>>Gerd



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