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mike155
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Joined: 17 Sep 2010
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 Posted: Mon Dec 17, 2018 2:38 pm Post subject: |
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| 5ace wrote: | | Compile @world with -march=generic |
You shouldn't that, because '-march=generic' is invalid. The GCC man page says:
| Quote: | | There is no -march=generic option because -march indicates the instruction set the compiler can use, and there is no generic instruction set applicable to all processors |
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NeddySeagoon
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| Posted: Mon Dec 17, 2018 2:40 pm Post subject: |
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C5ace,
That will be -march unset and -mtune=generic.
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NeddySeagoon
Computer users fall into two groups:-
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mike155
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| Posted: Mon Dec 17, 2018 2:53 pm Post subject: |
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| erm67 wrote: | | -march local on x86 CPU is usually more powerful |
Sorry, but GCC does not support '-march local'. Did you mean "-march=native"? |
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erm67
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Joined: 01 Nov 2005
Posts: 445
Location: EU
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| Posted: Mon Dec 17, 2018 2:53 pm Post subject: |
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| mike155 wrote: | | erm67 wrote: | | -march local on x86 CPU is usually more powerful |
Sorry, but GCC does not support '-march local'. Did you mean "-march=native"? |
of course, sorry
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Ok boomer
True ignorance is not the absence of knowledge, but the refusal to acquire it.
Ab esse ad posse valet, a posse ad esse non valet consequentia
My fediverse account: @erm67@erm67.dynu.net |
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Cuong Nguyen
Tux's lil' helper
Joined: 18 Jan 2018
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| Posted: Mon Dec 17, 2018 3:39 pm Post subject: |
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| erm67 wrote: | | -march local on x86 CPU is usually more powerful that -march=<cpu name> because it also tunes for the cache size of the current CPU |
Indeed, there are 3 params of CPU cache settings, vary upon CPU sub-specs for Server or Laptop
For example:
For server:
--param l2-cache-size=12288 -mtune=westmere
For laptop:
--param l2-cache-size=3072 -mtune=ivybridge
L2-cache for laptop is 1/4 as for server. |
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erm67
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Posts: 445
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| Posted: Mon Dec 17, 2018 5:47 pm Post subject: |
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There are also other flags beside ther CPU model ones like the ones set by gentooLTO:
https://github.com/InBetweenNames/gentooLTO
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Ok boomer
True ignorance is not the absence of knowledge, but the refusal to acquire it.
Ab esse ad posse valet, a posse ad esse non valet consequentia
My fediverse account: @erm67@erm67.dynu.net |
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