Messages in this thread | | | Date | Thu, 6 Sep 2012 10:22:19 +0300 (EEST) | From | Pekka Enberg <> | Subject | Re: [PATCH -v3 14/14] x86, mm: Map ISA area with connected ram range at the same time |
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On Wed, Sep 5, 2012 at 1:02 AM, Pekka Enberg <penberg@kernel.org> wrote: > > How significant is the speed gain? The "isa_done" flag makes code flow > > more difficult to follow.
On Wed, 5 Sep 2012, Yinghai Lu wrote: > Not really much. > > when booting system: > memmap=16m$128m memmap=16m$512m memmap=16m$256m memmap=16m$768m memmap=16m$1024m > > with the patch > [ 0.000000] init_memory_mapping: [mem 0x00000000-0x07ffffff] > [ 0.000000] [mem 0x00000000-0x07ffffff] page 2M > [ 0.000000] init_memory_mapping: [mem 0x09000000-0x0fffffff] > [ 0.000000] [mem 0x09000000-0x0fffffff] page 2M > [ 0.000000] init_memory_mapping: [mem 0x11000000-0x1fffffff] > [ 0.000000] [mem 0x11000000-0x1fffffff] page 2M > [ 0.000000] init_memory_mapping: [mem 0x21000000-0x2fffffff] > [ 0.000000] [mem 0x21000000-0x2fffffff] page 2M > [ 0.000000] init_memory_mapping: [mem 0x31000000-0x3fffffff] > [ 0.000000] [mem 0x31000000-0x3fffffff] page 2M > [ 0.000000] init_memory_mapping: [mem 0x41000000-0x7fffdfff] > [ 0.000000] [mem 0x41000000-0x7fdfffff] page 2M > [ 0.000000] [mem 0x7fe00000-0x7fffdfff] page 4k > > otherwise will have > > [ 0.000000] init_memory_mapping: [mem 0x00000000-0x000fffff] > [ 0.000000] [mem 0x00000000-0x000fffff] page 4k > [ 0.000000] init_memory_mapping: [mem 0x00100000-0x07ffffff] > [ 0.000000] [mem 0x00100000-0x001fffff] page 4k > [ 0.000000] [mem 0x00200000-0x07ffffff] page 2M > [ 0.000000] init_memory_mapping: [mem 0x09000000-0x0fffffff] > [ 0.000000] [mem 0x09000000-0x0fffffff] page 2M > [ 0.000000] init_memory_mapping: [mem 0x11000000-0x1fffffff] > [ 0.000000] [mem 0x11000000-0x1fffffff] page 2M > [ 0.000000] init_memory_mapping: [mem 0x21000000-0x2fffffff] > [ 0.000000] [mem 0x21000000-0x2fffffff] page 2M > [ 0.000000] init_memory_mapping: [mem 0x31000000-0x3fffffff] > [ 0.000000] [mem 0x31000000-0x3fffffff] page 2M > [ 0.000000] init_memory_mapping: [mem 0x41000000-0x7fffdfff] > [ 0.000000] [mem 0x41000000-0x7fdfffff] page 2M > [ 0.000000] [mem 0x7fe00000-0x7fffdfff] page 4k
OK. Is there any other reason than performance to do this?
Pekka
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