SwitchToThread vs Sleep(0)

[dedndave]

it's attached in reply #57, Alex

here is version 1.0, which has the serialization code
but, version 1.1 is a little better, i think

[Antariy]

Ah, then results in my previous message was for right thing - those results are for dTime2.zip, but I thought maybe I missed something.

[Antariy]

Results for dTime1.zip:

Code: [Select]

4 34 0 0 10 7 7 20 33 13
27 32 51 82 21 8 22 24 24 26
65 67 79 104 104 92 74 135 36 74
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[dedndave]

thanks, Alex   :t

as i suspected, dTime2 is better
it still needs work, but i like certain features

1) the code to be timed is in a PROC, rather than using macros before and after
    and, the timing function is a PROC
2) the function allows adjustment of thread priority level
3) the loop count has been eliminated
    we know from experience that a run of ~0.5 seconds yields good results
    so, the dTime function runs until time has elapsed, rather than some pre-determined loop count
4) we try to eliminate the use of CPUID to serialize code

[FORTRANS]

Hi Dave,

   Dtime2 results from the oldies.

Cheers,

Steve N.

Code: [Select]

P-III
4 3 2 3 5 0 0 0 3 2
99 97 95 95 95 96 102 98 93 100
117 114 110 120 122 118 120 121 117 121
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P-MMX
4 3 4 4 4 5 4 4 4 4
19 19 60 9 19 20 21 19 19 19
137 130 126 130 130 133 130 130 130 130
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Pentium M
3 3 3 0 5 3 4 3 3 0
118 118 126 135 113 124 119 118 118 118
32 34 34 35 34 34 34 34 34 34
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[dedndave]

thanks Steve
the results are fairly stable
it's cool to see the differences, as processors evolved   :P

[jj2007]

Hi Dave,
You will love this one - AMD Athlon:
39 40 40 40 40 40 40 40 40 40
80 80 80 80 80 80 80 80 80 80
120 120 120 120 120 127 120 120 120 120

[dedndave]

those are great numbers, Jochen   

still, some issues to work out
i will play with it more tomorrow

what do you think of the code ?

[jj2007]

what do you think of the code ?

Looks ok, but seems not to like some other CPUs ;-)

In the meantime, I've worked out something based on Michael's idea. Here are some results for the timeslice length:

Intel(R) Core(TM) i5-2450M CPU @ 2.50GHz (SSE4)
6       valid tests, 116714     avg kCycles
7       valid tests, 116547     avg kCycles
6       valid tests, 116796     avg kCycles
7       valid tests, 116774     avg kCycles
7       valid tests, 116523     avg kCycles
5       valid tests, 116784     avg kCycles
7       valid tests, 116728     avg kCycles
6       valid tests, 116711     avg kCycles
6       valid tests, 116722     avg kCycles
8       valid tests, 116493     avg kCycles

Intel(R) Celeron(R) M CPU        420  @ 1.60GHz (SSE3)
9       valid tests, 49989      avg kCycles
10      valid tests, 49811      avg kCycles
9       valid tests, 50027      avg kCycles
9       valid tests, 49934      avg kCycles
9       valid tests, 49973      avg kCycles
9       valid tests, 50028      avg kCycles
10      valid tests, 49887      avg kCycles
9       valid tests, 49899      avg kCycles
9       valid tests, 50019      avg kCycles
10      valid tests, 49805      avg kCycles

[Gunther]

Jochen,

my results:

Code: [Select]

Intel(R) Core(TM) i7-3770 CPU @ 3.40GHz (SSE4)
10      valid tests, 158126     avg kCycles
8       valid tests, 158434     avg kCycles
8       valid tests, 158700     avg kCycles
9       valid tests, 158526     avg kCycles
5       valid tests, 158665     avg kCycles
10      valid tests, 137386     avg kCycles
8       valid tests, 158749     avg kCycles
8       valid tests, 158870     avg kCycles
9       valid tests, 158754     avg kCycles
8       valid tests, 158651     avg kCycles
ok

Gunther

[dedndave]

that seems to look pretty good on my prescott   

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Intel(R) Pentium(R) 4 CPU 3.00GHz (SSE3)
9       valid tests, 93738      avg kCycles
9       valid tests, 93644      avg kCycles
9       valid tests, 93766      avg kCycles
10      valid tests, 93547      avg kCycles
9       valid tests, 93741      avg kCycles
9       valid tests, 93710      avg kCycles
9       valid tests, 93745      avg kCycles
9       valid tests, 93782      avg kCycles
9       valid tests, 93754      avg kCycles
9       valid tests, 93799      avg kCycles

[Antariy]

Hi Jochen :t

Code: [Select]

Intel(R) Celeron(R) CPU 2.13GHz (SSE3)
9       valid tests, 65206      avg kCycles
9       valid tests, 66479      avg kCycles
9       valid tests, 66365      avg kCycles
9       valid tests, 66431      avg kCycles
10      valid tests, 66133      avg kCycles
10      valid tests, 66256      avg kCycles
9       valid tests, 66600      avg kCycles
9       valid tests, 66179      avg kCycles
10      valid tests, 65903      avg kCycles
9       valid tests, 66016      avg kCycles
ok

[Obivan]

Hi Jochen,

here my results:

Code: [Select]

Intel(R) Xeon(R) CPU E31230 @ 3.20GHz (SSE4)
10      valid tests, 102589     avg kCycles
9       valid tests, 103229     avg kCycles
10      valid tests, 102377     avg kCycles
10      valid tests, 102594     avg kCycles
9       valid tests, 102947     avg kCycles
9       valid tests, 102224     avg kCycles
9       valid tests, 102925     avg kCycles
10      valid tests, 102337     avg kCycles
10      valid tests, 103004     avg kCycles
10      valid tests, 102270     avg kCycles

[jj2007]

Thanks, Obivan, Alex, Dave and Gunther.

Results look pretty stable now, the next step would be to design a timer macro that starts at the beginning of the time slice and stops shortly before... if I find time ;-)

[dedndave]

from what i am seeing, we don't violate that rule if we use 0.5 seconds as a loop count target
or, am i droping a decimal point someplace - lol