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This is interesting. Guess what effect cpu frequency scaling has on |
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memcpy. I wonder if the difference has to do purely with the cpu |
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frequency, or if it's because the memory controller in on the die. |
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|
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At 1800 MHz: |
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$ ./memcpy 1808 1000 1048576 |
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Memory to memory copy rate = 1060.210815 MBytes / sec. Block size = 1048576. |
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|
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At 1000 MHz: |
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$ ./memcpy 1005 1000 1048576 |
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Memory to memory copy rate = 808.985352 MBytes / sec. Block size = 1048576. |
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|
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This is an unpatched glibc, of course. |
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|
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I've got a single 512MB stick of premium Corsair ram in it (the sister |
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stick lives in another computer until prices drop, at which time I will |
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buy another matched pair of the good stuff). |
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|
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The fact that I'm using only one stick and I'm getting speeds similar to |
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those using two, suggests to me that the strangely low numbers some |
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people are getting are not explained away by their using only a single |
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channel. |
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|
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-- |
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"Pluralitas non est ponenda sine necessitate" - W. of O. |
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|
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-- |
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gentoo-amd64@g.o mailing list |