- 15 4月, 2013 2 次提交
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由 Andy Shevchenko 提交于
As suggested by Peter Anvin. Signed-off-by: NAndy Shevchenko <andriy.shevchenko@linux.intel.com> Cc: H . Peter Anvin <hpa@linux.intel.com> Signed-off-by: NIngo Molnar <mingo@kernel.org>
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由 Andy Shevchenko 提交于
Apparently 'byts' should be 'bytes'. Signed-off-by: NAndy Shevchenko <andriy.shevchenko@linux.intel.com> Cc: H . Peter Anvin <hpa@linux.intel.com> Signed-off-by: NIngo Molnar <mingo@kernel.org>
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- 25 9月, 2010 1 次提交
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由 Ma Ling 提交于
movs instruction will combine data to accelerate moving data, however we need to concern two cases about it. 1. movs instruction need long lantency to startup, so here we use general mov instruction to copy data. 2. movs instruction is not good for unaligned case, even if src offset is 0x10, dest offset is 0x0, we avoid and handle the case by general mov instruction. Signed-off-by: NMa Ling <ling.ma@intel.com> LKML-Reference: <1284664360-6138-1-git-send-email-ling.ma@intel.com> Signed-off-by: NH. Peter Anvin <hpa@zytor.com>
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- 24 8月, 2010 2 次提交
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由 Ma Ling 提交于
All read operations after allocation stage can run speculatively, all write operation will run in program order, and if addresses are different read may run before older write operation, otherwise wait until write commit. However CPU don't check each address bit, so read could fail to recognize different address even they are in different page.For example if rsi is 0xf004, rdi is 0xe008, in following operation there will generate big performance latency. 1. movq (%rsi), %rax 2. movq %rax, (%rdi) 3. movq 8(%rsi), %rax 4. movq %rax, 8(%rdi) If %rsi and rdi were in really the same meory page, there are TRUE read-after-write dependence because instruction 2 write 0x008 and instruction 3 read 0x00c, the two address are overlap partially. Actually there are in different page and no any issues, but without checking each address bit CPU could think they are in the same page, and instruction 3 have to wait for instruction 2 to write data into cache from write buffer, then load data from cache, the cost time read spent is equal to mfence instruction. We may avoid it by tuning operation sequence as follow. 1. movq 8(%rsi), %rax 2. movq %rax, 8(%rdi) 3. movq (%rsi), %rax 4. movq %rax, (%rdi) Instruction 3 read 0x004, instruction 2 write address 0x010, no any dependence. At last on Core2 we gain 1.83x speedup compared with original instruction sequence. In this patch we first handle small size(less 20bytes), then jump to different copy mode. Based on our micro-benchmark small bytes from 1 to 127 bytes, we got up to 2X improvement, and up to 1.5X improvement for 1024 bytes on Corei7. (We use our micro-benchmark, and will do further test according to your requirment) Signed-off-by: NMa Ling <ling.ma@intel.com> LKML-Reference: <1277753065-18610-1-git-send-email-ling.ma@intel.com> Signed-off-by: NH. Peter Anvin <hpa@zytor.com>
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由 Ma, Ling 提交于
memmove() allow source and destination address to be overlap, but there is no such limitation for memcpy(). Therefore, explicitly implement memmove() in both the forwards and backward directions, to give us the ability to optimize memcpy(). Signed-off-by: NMa Ling <ling.ma@intel.com> LKML-Reference: <C10D3FB0CD45994C8A51FEC1227CE22F0E483AD86A@shsmsx502.ccr.corp.intel.com> Signed-off-by: NH. Peter Anvin <hpa@linux.intel.com>
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- 17 4月, 2008 1 次提交
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由 Paolo Ciarrocchi 提交于
Before: total: 2 errors, 0 warnings, 43 lines checked After: total: 0 errors, 0 warnings, 43 lines checked No code changed: arch/x86/lib/memcpy_32.o: text data bss dec hex filename 164 0 0 164 a4 memcpy_32.o.before 164 0 0 164 a4 memcpy_32.o.after md5: d759f55621af27f51720b59c8ca96a4d memcpy_32.o.before.asm d759f55621af27f51720b59c8ca96a4d memcpy_32.o.after.asm Signed-off-by: NPaolo Ciarrocchi <paolo.ciarrocchi@gmail.com> Signed-off-by: NIngo Molnar <mingo@elte.hu>
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- 30 1月, 2008 1 次提交
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由 Jan Engelhardt 提交于
x86: remove unneeded casts Signed-off-by: NJan Engelhardt <jengelh@computergmbh.de> Signed-off-by: NIngo Molnar <mingo@elte.hu> Signed-off-by: NThomas Gleixner <tglx@linutronix.de>
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- 11 10月, 2007 2 次提交
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由 Thomas Gleixner 提交于
Signed-off-by: NThomas Gleixner <tglx@linutronix.de> Signed-off-by: NIngo Molnar <mingo@elte.hu>
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由 Thomas Gleixner 提交于
Signed-off-by: NThomas Gleixner <tglx@linutronix.de> Signed-off-by: NIngo Molnar <mingo@elte.hu>
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- 01 7月, 2006 1 次提交
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由 Jörn Engel 提交于
Signed-off-by: NJörn Engel <joern@wohnheim.fh-wedel.de> Signed-off-by: NAdrian Bunk <bunk@stusta.de>
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- 17 4月, 2005 1 次提交
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由 Linus Torvalds 提交于
Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
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