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2012-07-03powerpc: POWER7 optimised copy_page using VMX and enhanced prefetchAnton Blanchard1-0/+4
Implement a POWER7 optimised copy_page using VMX and enhanced prefetch instructions. We use enhanced prefetch hints to prefetch both the load and store side. We copy a cacheline at a time and fall back to regular loads and stores if we are unable to use VMX (eg we are in an interrupt). The following microbenchmark was used to assess the impact of the patch: http://ozlabs.org/~anton/junkcode/page_fault_file.c We test MAP_PRIVATE page faults across a 1GB file, 100 times: # time ./page_fault_file -p -l 1G -i 100 Before: 22.25s After: 18.89s 17% faster Signed-off-by: Anton Blanchard <anton@samba.org> Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2011-05-19powerpc: Simplify 4k/64k copy_page logicAnton Blanchard1-3/+4
To make it easier to add optimised versions of copy_page, remove the 4kB loop for 64kB pages and just do all the work in copy_page. Signed-off-by: Anton Blanchard <anton@samba.org> Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2010-02-17powerpc: Pair loads and stores in copy_4k_pageAnton Blanchard1-14/+14
A number of our chips like loads and stores to be paired. A small kernel module testcase shows the improvement of pairing loads and stores in copy_4k_page: POWER6: +9% POWER7: +1.5% #include <linux/module.h> #include <linux/mm.h> #define ITERATIONS 10000000 static int __init copypage_init(void) { struct timespec before, after; unsigned long i; struct page *destpage, *srcpage; char *dest, *src; destpage = alloc_page(GFP_KERNEL); srcpage = alloc_page(GFP_KERNEL); dest = page_address(destpage); src = page_address(srcpage); getnstimeofday(&before); for (i = 0; i < ITERATIONS; i++) copy_4K_page(dest, src); getnstimeofday(&after); free_page((unsigned long)dest); free_page((unsigned long)src); printk(KERN_DEBUG "copy_4K_page loop took %lu ns\n", (after.tv_sec - before.tv_sec) * NSEC_PER_SEC + (after.tv_nsec - before.tv_nsec)); return 0; } static void __exit copypage_exit(void) { } module_init(copypage_init) module_exit(copypage_exit) MODULE_LICENSE("GPL"); MODULE_AUTHOR("Anton Blanchard"); Signed-off-by: Anton Blanchard <anton@samba.org> Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2009-10-28powerpc: perf_event: Cleanup copy_page output by hiding setup symbolAnton Blanchard1-2/+2
A lot of hits in "setup" doesn't make much sense, so hide this symbol and allow all the hits to end up in copy_4k_page. Signed-off-by: Anton Blanchard <anton@samba.org> Signed-off-by: Paul Mackerras <paulus@samba.org>
2008-09-15powerpc: New copy_4K_page()Mark Nelson1-105/+93
This new copy_4K_page() function was originally tuned for the best performance on the Cell processor, but after testing on more 64bit powerpc chips it was found that with a small modification it either matched the performance offered by the current mainline version or bettered it by a small amount. It was found that on a Cell-based QS22 blade the amount of system time measured when compiling a 2.6.26 pseries_defconfig decreased by 4%. Using the same test, a 4-way 970MP machine saw a decrease of 2% in system time. No noticeable change was seen on Power4, Power5 or Power6. The 4096 byte page is copied in thirty-two 128 byte strides. An initial setup loop executes dcbt instructions for the whole source page and dcbz instructions for the whole destination page. To do this, the cache line size is retrieved from ppc64_caches. A new CPU feature bit, CPU_FTR_CP_USE_DCBTZ, (introduced in the previous patch) is used to make the modification to this new copy routine - on Power4, 970 and Cell the feature bit is set so the setup loop is executed, but on all other 64bit chips the setup loop is nop'ed out. Signed-off-by: Mark Nelson <markn@au1.ibm.com> Signed-off-by: Paul Mackerras <paulus@samba.org>
2006-02-10[PATCH] powerpc: trivial: modify comments to refer to new location of filesJon Mason1-2/+0
This patch removes all self references and fixes references to files in the now defunct arch/ppc64 tree. I think this accomplises everything wanted, though there might be a few references I missed. Signed-off-by: Jon Mason <jdmason@us.ibm.com> Signed-off-by: Paul Mackerras <paulus@samba.org>
2005-11-06[PATCH] ppc64: support 64k pagesBenjamin Herrenschmidt1-1/+1
Adds a new CONFIG_PPC_64K_PAGES which, when enabled, changes the kernel base page size to 64K. The resulting kernel still boots on any hardware. On current machines with 4K pages support only, the kernel will maintain 16 "subpages" for each 64K page transparently. Note that while real 64K capable HW has been tested, the current patch will not enable it yet as such hardware is not released yet, and I'm still verifying with the firmware architects the proper to get the information from the newer hypervisors. Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-10-10powerpc: Rename files to have consistent _32/_64 suffixesPaul Mackerras1-0/+121
This doesn't change any code, just renames things so we consistently have foo_32.c and foo_64.c where we have separate 32- and 64-bit versions. Signed-off-by: Paul Mackerras <paulus@samba.org>

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