summaryrefslogtreecommitdiff
path: root/lib/raid6/avx2.c
AgeCommit message (Collapse)AuthorFilesLines
2022-01-06lib/raid6: Use strict priority ranking for pq gen() benchmarkingDirk Müller1-4/+4
On x86_64, currently 3 variants of AVX512, 3 variants of AVX2 and 3 variants of SSE2 are benchmarked on initialization, taking between 144-153 jiffies. Testing across a hardware pool of various generations of intel cpus I could not find a single case where SSE2 won over AVX2 or AVX512. There are cases where AVX2 wins over AVX512 however. Change "prefer" into an integer priority field (similar to how recov selection works) to have more than one ranking level available, which is backwards compatible with existing behavior. Give AVX2/512 variants higher priority over SSE2 in order to skip SSE testing when AVX is available. in a AVX2/x86_64/HZ=250 case this saves in the order of 200ms of initialization time. Signed-off-by: Dirk Müller <dmueller@suse.de> Acked-by: Paul Menzel <pmenzel@molgen.mpg.de> Signed-off-by: Song Liu <song@kernel.org>
2020-04-08x86: update AS_* macros to binutils >=2.23, supporting ADX and AVX2Jason A. Donenfeld1-4/+0
Now that the kernel specifies binutils 2.23 as the minimum version, we can remove ifdefs for AVX2 and ADX throughout. Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com> Acked-by: Ingo Molnar <mingo@kernel.org> Reviewed-by: Nick Desaulniers <ndesaulniers@google.com> Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
2019-05-24treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 48Thomas Gleixner1-7/+1
Based on 1 normalized pattern(s): this program is free software you can redistribute it and or modify it under the terms of the gnu general public license as published by the free software foundation inc 53 temple place ste 330 boston ma 02111 1307 usa either version 2 of the license or at your option any later version incorporated herein by reference extracted by the scancode license scanner the SPDX license identifier GPL-2.0-or-later has been chosen to replace the boilerplate/reference in 13 file(s). Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Reviewed-by: Allison Randal <allison@lohutok.net> Reviewed-by: Kate Stewart <kstewart@linuxfoundation.org> Cc: linux-spdx@vger.kernel.org Link: https://lkml.kernel.org/r/20190520170858.645641371@linutronix.de Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2016-11-08lib/raid6: Add AVX2 optimized xor_syndrome functionsGayatri Kammela1-3/+229
Implement the AVX2 optimization of RAID6 xor_syndrome functions which is simply based on sse2.c written by hpa. Cc: H. Peter Anvin <hpa@linux.intel.com> Cc: Yuanhan Liu <yuanhan.liu@intel.com> Cc: Fenghua Yu <fenghua.yu@intel.com> Signed-off-by: Gayatri Kammela <gayatri.kammela@intel.com> Signed-off-by: Shaohua Li <shli@fb.com>
2015-04-22md/raid6 algorithms: delta syndrome functionsMarkus Stockhausen1-0/+3
v3: s-o-b comment, explanation of performance and descision for the start/stop implementation Implementing rmw functionality for RAID6 requires optimized syndrome calculation. Up to now we can only generate a complete syndrome. The target P/Q pages are always overwritten. With this patch we provide a framework for inplace P/Q modification. In the first place simply fill those functions with NULL values. xor_syndrome() has two additional parameters: start & stop. These will indicate the first and last page that are changing during a rmw run. That makes it possible to avoid several unneccessary loops and speed up calculation. The caller needs to implement the following logic to make the functions work. 1) xor_syndrome(disks, start, stop, ...): "Remove" all data of source blocks inside P/Q between (and including) start and end. 2) modify any block with start <= block <= stop 3) xor_syndrome(disks, start, stop, ...): "Reinsert" all data of source blocks into P/Q between (and including) start and end. Pages between start and stop that won't be changed should be filled with a pointer to the kernel zero page. The reasons for not taking NULL pages are: 1) Algorithms cross the whole source data line by line. Thus avoid additional branches. 2) Having a NULL page avoids calculating the XOR P parity but still need calulation steps for the Q parity. Depending on the algorithm unrolling that might be only a difference of 2 instructions per loop. The benchmark numbers of the gen_syndrome() functions are displayed in the kernel log. Do the same for the xor_syndrome() functions. This will help to analyze performance problems and give an rough estimate how well the algorithm works. The choice of the fastest algorithm will still depend on the gen_syndrome() performance. With the start/stop page implementation the speed can vary a lot in real life. E.g. a change of page 0 & page 15 on a stripe will be harder to compute than the case where page 0 & page 1 are XOR candidates. To be not to enthusiatic about the expected speeds we will run a worse case test that simulates a change on the upper half of the stripe. So we do: 1) calculation of P/Q for the upper pages 2) continuation of Q for the lower (empty) pages Signed-off-by: Markus Stockhausen <stockhausen@collogia.de> Signed-off-by: NeilBrown <neilb@suse.de>
2012-12-13lib/raid6: Add AVX2 optimized gen_syndrome functionsYuanhan Liu1-0/+251
Add AVX2 optimized gen_syndrom functions, which is simply based on sse2.c written by hpa. Signed-off-by: Yuanhan Liu <yuanhan.liu@linux.intel.com> Reviewed-by: H. Peter Anvin <hpa@zytor.com> Signed-off-by: Jim Kukunas <james.t.kukunas@linux.intel.com> Signed-off-by: NeilBrown <neilb@suse.de>