- 24 3月, 2012 1 次提交
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由 Bob Pearson 提交于
This patchset (re)uses Bob Pearson's crc32 slice-by-8 code to stamp out a software crc32c implementation. It removes the crc32c implementation in crypto/ in favor of using the stamped-out one in lib/. There is also a change to Kconfig so that the kernel builder can pick an implementation best suited for the hardware. The motivation for this patchset is that I am working on adding full metadata checksumming to ext4. As far as performance impact of adding checksumming goes, I see nearly no change with a standard mail server ffsb simulation. On a test that involves only file creation and deletion and extent tree writes, I see a drop of about 50 pcercent with the current kernel crc32c implementation; this improves to a drop of about 20 percent with the enclosed crc32c code. When metadata is usually a small fraction of total IO, this new implementation doesn't help much because metadata is usually a small fraction of total IO. However, when we are doing IO that is almost all metadata (such as rm -rf'ing a tree), then this patch speeds up the operation substantially. Incidentally, given that iscsi, sctp, and btrfs also use crc32c, this patchset should improve their speed as well. I have not yet quantified that, however. This latest submission combines Bob's patches from late August 2011 with mine so that they can be one coherent patch set. Please excuse my inability to combine some of the patches; I've been advised to leave Bob's patches alone and build atop them instead. :/ Since the last posting, I've also collected some crc32c test results on a bunch of different x86/powerpc/sparc platforms. The results can be viewed here: http://goo.gl/sgt3i ; the "crc32-kern-le" and "crc32c" columns describe the performance of the kernel's current crc32 and crc32c software implementations. The "crc32c-by8-le" column shows crc32c performance with this patchset applied. I expect crc32 performance to be roughly the same. The two _boost columns at the right side of the spreadsheet shows how much faster the new implementation is over the old one. As you can see, crc32 rises substantially, and crc32c experiences a huge increase. This patch: - remove trailing whitespace from lib/crc32.c - remove trailing whitespace from lib/crc32defs.h [djwong@us.ibm.com: changelog tweaks] Signed-off-by: NBob Pearson <rpearson@systemfabricworks.com> Signed-off-by: NDarrick J. Wong <djwong@us.ibm.com> Signed-off-by: NAndrew Morton <akpm@linux-foundation.org> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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- 11 1月, 2012 1 次提交
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由 Joakim Tjernlund 提交于
Taking a pointer reference to each row in the crc table matrix, one can reduce the inner loop with a few insn's Signed-off-by: NJoakim Tjernlund <Joakim.Tjernlund@transmode.se> Cc: Bob Pearson <rpearson@systemfabricworks.com> Cc: Frank Zago <fzago@systemfabricworks.com> Cc: Eric Dumazet <eric.dumazet@gmail.com> Signed-off-by: NAndrew Morton <akpm@linux-foundation.org> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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- 27 7月, 2011 1 次提交
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由 Arun Sharma 提交于
This allows us to move duplicated code in <asm/atomic.h> (atomic_inc_not_zero() for now) to <linux/atomic.h> Signed-off-by: NArun Sharma <asharma@fb.com> Reviewed-by: NEric Dumazet <eric.dumazet@gmail.com> Cc: Ingo Molnar <mingo@elte.hu> Cc: David Miller <davem@davemloft.net> Cc: Eric Dumazet <eric.dumazet@gmail.com> Acked-by: NMike Frysinger <vapier@gentoo.org> Signed-off-by: NAndrew Morton <akpm@linux-foundation.org> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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- 26 5月, 2010 1 次提交
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由 Andrew Morton 提交于
It doesn't work on big-endian - those architectures don't define __LITTLE_ENDIAN. Cc: Joakim Tjernlund <joakim.tjernlund@transmode.se> Reported-by: NStephen Rothwell <sfr@canb.auug.org.au> Signed-off-by: NAndrew Morton <akpm@linux-foundation.org> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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- 25 5月, 2010 2 次提交
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由 Joakim Tjernlund 提交于
Since crc32.c contains a nifty test program that can be executed in user space, make sure endian detection works reliably in user space too. Signed-off-by: NJoakim Tjernlund <Joakim.Tjernlund@transmode.se> Signed-off-by: NAndrew Morton <akpm@linux-foundation.org> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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由 Joakim Tjernlund 提交于
Precompute more crc32 values(0xcc00, 0xcc0000 and 0xcc000000) into tables. This increases the table size from 1KB to 4KB but the performance benfit makes it worth it: 28% faster on MPC8321, 266 MHz 2x faster on Core 2 Duo, 3.1GHz [akpm@linux-foundation.org: coding-style fixes] Signed-off-by: NJoakim Tjernlund <Joakim.Tjernlund@transmode.se> Signed-off-by: NAndrew Morton <akpm@linux-foundation.org> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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- 30 3月, 2010 1 次提交
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由 Tejun Heo 提交于
include cleanup: Update gfp.h and slab.h includes to prepare for breaking implicit slab.h inclusion from percpu.h percpu.h is included by sched.h and module.h and thus ends up being included when building most .c files. percpu.h includes slab.h which in turn includes gfp.h making everything defined by the two files universally available and complicating inclusion dependencies. percpu.h -> slab.h dependency is about to be removed. Prepare for this change by updating users of gfp and slab facilities include those headers directly instead of assuming availability. As this conversion needs to touch large number of source files, the following script is used as the basis of conversion. http://userweb.kernel.org/~tj/misc/slabh-sweep.py The script does the followings. * Scan files for gfp and slab usages and update includes such that only the necessary includes are there. ie. if only gfp is used, gfp.h, if slab is used, slab.h. * When the script inserts a new include, it looks at the include blocks and try to put the new include such that its order conforms to its surrounding. It's put in the include block which contains core kernel includes, in the same order that the rest are ordered - alphabetical, Christmas tree, rev-Xmas-tree or at the end if there doesn't seem to be any matching order. * If the script can't find a place to put a new include (mostly because the file doesn't have fitting include block), it prints out an error message indicating which .h file needs to be added to the file. The conversion was done in the following steps. 1. The initial automatic conversion of all .c files updated slightly over 4000 files, deleting around 700 includes and adding ~480 gfp.h and ~3000 slab.h inclusions. The script emitted errors for ~400 files. 2. Each error was manually checked. Some didn't need the inclusion, some needed manual addition while adding it to implementation .h or embedding .c file was more appropriate for others. This step added inclusions to around 150 files. 3. The script was run again and the output was compared to the edits from #2 to make sure no file was left behind. 4. Several build tests were done and a couple of problems were fixed. e.g. lib/decompress_*.c used malloc/free() wrappers around slab APIs requiring slab.h to be added manually. 5. The script was run on all .h files but without automatically editing them as sprinkling gfp.h and slab.h inclusions around .h files could easily lead to inclusion dependency hell. Most gfp.h inclusion directives were ignored as stuff from gfp.h was usually wildly available and often used in preprocessor macros. Each slab.h inclusion directive was examined and added manually as necessary. 6. percpu.h was updated not to include slab.h. 7. Build test were done on the following configurations and failures were fixed. CONFIG_GCOV_KERNEL was turned off for all tests (as my distributed build env didn't work with gcov compiles) and a few more options had to be turned off depending on archs to make things build (like ipr on powerpc/64 which failed due to missing writeq). * x86 and x86_64 UP and SMP allmodconfig and a custom test config. * powerpc and powerpc64 SMP allmodconfig * sparc and sparc64 SMP allmodconfig * ia64 SMP allmodconfig * s390 SMP allmodconfig * alpha SMP allmodconfig * um on x86_64 SMP allmodconfig 8. percpu.h modifications were reverted so that it could be applied as a separate patch and serve as bisection point. Given the fact that I had only a couple of failures from tests on step 6, I'm fairly confident about the coverage of this conversion patch. If there is a breakage, it's likely to be something in one of the arch headers which should be easily discoverable easily on most builds of the specific arch. Signed-off-by: NTejun Heo <tj@kernel.org> Guess-its-ok-by: NChristoph Lameter <cl@linux-foundation.org> Cc: Ingo Molnar <mingo@redhat.com> Cc: Lee Schermerhorn <Lee.Schermerhorn@hp.com>
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- 07 3月, 2010 1 次提交
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由 Joakim Tjernlund 提交于
Signed-off-by: NJoakim Tjernlund <Joakim.Tjernlund@transmode.se> Signed-off-by: NAndrew Morton <akpm@linux-foundation.org> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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- 16 12月, 2009 1 次提交
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由 Joakim Tjernlund 提交于
Move common crc body to new function crc32_body() cleaup and micro optimize crc32_body for speed and less size. [akpm@linux-foundation.org: coding-style fixes] Signed-off-by: NJoakim Tjernlund <Joakim.Tjernlund@transmode.se> Signed-off-by: NAndrew Morton <akpm@linux-foundation.org> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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- 03 2月, 2008 1 次提交
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由 Joe Perches 提交于
Signed-off-by: NJoe Perches <joe@perches.com> Signed-off-by: NAdrian Bunk <bunk@kernel.org>
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- 19 10月, 2007 1 次提交
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由 Ralf Baechle 提交于
To be consistent with the use of attributes in the rest of the kernel replace all use of __attribute_pure__ with __pure and delete the definition of __attribute_pure__. Signed-off-by: NRalf Baechle <ralf@linux-mips.org> Cc: Russell King <rmk@arm.linux.org.uk> Acked-by: NMauro Carvalho Chehab <mchehab@infradead.org> Cc: Bryan Wu <bryan.wu@analog.com> Cc: Paul Mackerras <paulus@samba.org> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Signed-off-by: NAndrew Morton <akpm@linux-foundation.org> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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- 09 12月, 2006 1 次提交
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由 Akinobu Mita 提交于
This patch replaces bitreverse() by bitrev32. The only users of bitreverse() are crc32 itself and via-velocity. Cc: Jeff Garzik <jgarzik@pobox.com> Cc: Matt Domsch <Matt_Domsch@dell.com> Signed-off-by: NAkinobu Mita <akinobu.mita@gmail.com> Signed-off-by: NAndrew Morton <akpm@osdl.org> Signed-off-by: NLinus Torvalds <torvalds@osdl.org>
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- 26 6月, 2006 1 次提交
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由 Randy Dunlap 提交于
Make kernel-doc corrections & additions to lib/crc*.c. Add crc functions to kernel-api.tmpl in DocBook. Signed-off-by: NRandy Dunlap <rdunlap@xenotime.net> Signed-off-by: NAndrew Morton <akpm@osdl.org> Signed-off-by: NLinus Torvalds <torvalds@osdl.org>
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- 08 8月, 2005 1 次提交
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由 Dominik Hackl 提交于
This patch fixes a typo in lib/crc32.c which results in incorrect debug output. Signed-off-by: NDominik Hackl <dominik@hackl.dhs.org> Signed-off-by: NAndrew Morton <akpm@osdl.org> Signed-off-by: NLinus Torvalds <torvalds@osdl.org>
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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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