It is always helpful to have a test tool in place if we implement
new data critical algorithms. So add some test routines to the raid6
checker that can prove if the new xor_syndrome() works as expected.
Run through all permutations of start/stop pages per algorithm and
simulate a xor_syndrome() assisted rmw run. After each rmw check if
the recovery algorithm still confirms that the stripe is fine.
Signed-off-by: Markus Stockhausen <stockhausen@collogia.de>
Signed-off-by: NeilBrown <neilb@suse.de>
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>
Just like for AVX2 (which simply needs an #if -> #ifdef conversion),
SSSE3 assembler support should be checked for before using it.
Signed-off-by: Jan Beulich <jbeulich@suse.com>
Cc: Jim Kukunas <james.t.kukunas@linux.intel.com>
Acked-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: NeilBrown <neilb@suse.de>
Headline item is multithreading for RAID5 so that more
IO/sec can be supported on fast (SSD) devices.
Also TILE-Gx SIMD suppor for RAID6 calculations and an
assortment of bug fixes.
-----BEGIN PGP SIGNATURE-----
Version: GnuPG v2.0.19 (GNU/Linux)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=zLxh
-----END PGP SIGNATURE-----
Merge tag 'md/3.12' of git://neil.brown.name/md
Pull md update from Neil Brown:
"Headline item is multithreading for RAID5 so that more IO/sec can be
supported on fast (SSD) devices. Also TILE-Gx SIMD suppor for RAID6
calculations and an assortment of bug fixes"
* tag 'md/3.12' of git://neil.brown.name/md:
raid5: only wakeup necessary threads
md/raid5: flush out all pending requests before proceeding with reshape.
md/raid5: use seqcount to protect access to shape in make_request.
raid5: sysfs entry to control worker thread number
raid5: offload stripe handle to workqueue
raid5: fix stripe release order
raid5: make release_stripe lockless
md: avoid deadlock when dirty buffers during md_stop.
md: Don't test all of mddev->flags at once.
md: Fix apparent cut-and-paste error in super_90_validate
raid6/test: replace echo -e with printf
RAID: add tilegx SIMD implementation of raid6
md: fix safe_mode buglet.
md: don't call md_allow_write in get_bitmap_file.
-e is a non-standard echo option, echo output is
implementation-dependent when it is used. Replace echo -e with printf as
suggested by POSIX echo manual.
Cc: NeilBrown <neilb@suse.de>
Cc: Jim Kukunas <james.t.kukunas@linux.intel.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Yuanhan Liu <yuanhan.liu@linux.intel.com>
Acked-by: H. Peter Anvin <hpa@zytor.com>
Signed-off-by: Max Filippov <jcmvbkbc@gmail.com>
Signed-off-by: NeilBrown <neilb@suse.de>
This change adds TILE-Gx SIMD instructions to the software raid
(md), modeling the Altivec implementation. This is only for Syndrome
generation; there is more that could be done to improve recovery,
as in the recent Intel SSE3 recovery implementation.
The code unrolls 8 times; this turns out to be the best on tilegx
hardware among the set 1, 2, 4, 8 or 16. The code reads one
cache-line of data from each disk, stores P and Q then goes to the
next cache-line.
The test code in sys/linux/lib/raid6/test reports 2008 MB/s data
read rate for syndrome generation using 18 disks (16 data and 2
parity). It was 1512 MB/s before this SIMD optimizations. This is
running on 1 core with all the data in cache.
This is based on the paper The Mathematics of RAID-6.
(http://kernel.org/pub/linux/kernel/people/hpa/raid6.pdf).
Signed-off-by: Ken Steele <ken@tilera.com>
Signed-off-by: Chris Metcalf <cmetcalf@tilera.com>
Signed-off-by: NeilBrown <neilb@suse.de>
Rebased/reworked a patch contributed by Rob Herring that uses
NEON intrinsics to perform the RAID-6 syndrome calculations.
It uses the existing unroll.awk code to generate several
unrolled versions of which the best performing one is selected
at boot time.
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Acked-by: Nicolas Pitre <nico@linaro.org>
Cc: hpa@linux.intel.com
sse and avx2 stuff only exist on x86 arch, and we don't need to build
altivec on x86. And we can do that at lib/raid6/Makefile.
Proposed-by: H. Peter Anvin <hpa@zytor.com>
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>
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>
Optimize RAID6 recovery functions to take advantage of
the 256-bit YMM integer instructions introduced in AVX2.
The patch was tested and benchmarked before submission.
However hardware is not yet released so benchmark numbers
cannot be reported.
Acked-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>
Make the recovery functions static to fix the following sparse warnings:
lib/raid6/recov.c:25:6: warning: symbol 'raid6_2data_recov_intx1' was
not declared. Should it be static?
lib/raid6/recov.c:69:6: warning: symbol 'raid6_datap_recov_intx1' was
not declared. Should it be static?
lib/raid6/recov_ssse3.c:22:6: warning: symbol 'raid6_2data_recov_ssse3'
was not declared. Should it be static?
lib/raid6/recov_ssse3.c:197:6: warning: symbol 'raid6_datap_recov_ssse3'
was not declared. Should it be static?
Reported-by: Fengguang Wu <fengguang.wu@intel.com>
Signed-off-by: Jim Kukunas <james.t.kukunas@linux.intel.com>
Signed-off-by: NeilBrown <neilb@suse.de>
Reorders functions in raid6_algos as well as the preference check
to reduce the number of functions tested on initialization.
Also, creates symmetry between choosing the gen_syndrome functions
and choosing the recovery functions.
Signed-off-by: Jim Kukunas <james.t.kukunas@linux.intel.com>
Signed-off-by: NeilBrown <neilb@suse.de>
Test each combination of recovery and syndrome generation
functions.
Signed-off-by: Jim Kukunas <james.t.kukunas@linux.intel.com>
Signed-off-by: NeilBrown <neilb@suse.de>
Add SSSE3 optimized recovery functions, as well as a system
for selecting the most appropriate recovery functions to use.
Originally-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>
<linux/module.h> drags in headers which are not visible to userspace,
thus breaking the build for the test program.
Signed-off-by: Jim Kukunas <james.t.kukunas@linux.intel.com>
Signed-off-by: NeilBrown <neilb@suse.de>
Remove all #inclusions of asm/system.h preparatory to splitting and killing
it. Performed with the following command:
perl -p -i -e 's!^#\s*include\s*<asm/system[.]h>.*\n!!' `grep -Irl '^#\s*include\s*<asm/system[.]h>' *`
Signed-off-by: David Howells <dhowells@redhat.com>
Disintegrate asm/system.h for PowerPC.
Signed-off-by: David Howells <dhowells@redhat.com>
Acked-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
cc: linuxppc-dev@lists.ozlabs.org
These files were getting the defines for EXPORT_SYMBOL because
device.h was including module.h. But we are going to put an
end to that. So add the proper export.h include now.
Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
A pending cleanup will mean that module.h won't be implicitly
everywhere anymore. Make sure the modular drivers in md dir
are actually calling out for <module.h> explicitly in advance.
Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
The files were renamed in commit cc4589ebf; fix the name in the file
itself.
Signed-off-by: Dan McGee <dpmcgee@gmail.com>
Signed-off-by: NeilBrown <neilb@suse.de>
