Re: [GIT PULL] MD update for 4.9

[Shaohua Li <shli@kernel.org>]

On Thu, Oct 06, 2016 at 10:39:21PM -0700, Doug Dumitru wrote:
> Mr. Li,
> 
> There is another thread in [linux-raid] discussing pre-fetches in the
> raid-6 AVX2 code.  My testing implies that the prefetch distance is
> too short.  In your new AVX512 code, it looks like there are 24
> instructions, each with latencies of 1, between the prefetch and the
> actual memory load.  I don't have a AVX512 CPU to try this on, but the
> prefetch might do better at a bigger distance.  If I am not mistaken,
> it takes a lot longer than 24 clocks to fetch 4 cache lines.
> 
> Just a comment while the code is still fluid.

I did try your patch and it improved 10% in my machine, but this isn't
relevent to the pull. We can do the tunning later if necessary. I'm
hoping the intel guys can share some hints, but apparently Linus isn't a
fan for such tuning.

Thanks,
Shaohua

> On Thu, Oct 6, 2016 at 5:38 PM, Shaohua Li <shli@kernel.org> wrote:
> > Hi Linus,
> > Please pull MD update for 4.9. This update includes:
> > - new AVX512 instruction based raid6 gen/recovery algorithm
> > - A couple of md-cluster related bug fixes
> > - Fix a potential deadlock
> > - Set nonrotational bit for raid array with SSD
> > - Set correct max_hw_sectors for raid5/6, which hopefuly can improve
> >   performance a little bit
> > - Other minor fixes
> >
> > Thanks,
> > Shaohua
> >
> > The following changes since commit 7d1e042314619115153a0f6f06e4552c09a50e13:
> >
> >   Merge tag 'usercopy-v4.8-rc8' of git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux (2016-09-20 17:11:19 -0700)
> >
> > are available in the git repository at:
> >
> >   git://git.kernel.org/pub/scm/linux/kernel/git/shli/md.git tags/md/4.9-rc1
> >
> > for you to fetch changes up to bb086a89a406b5d877ee616f1490fcc81f8e1b2b:
> >
> >   md: set rotational bit (2016-10-03 10:20:27 -0700)
> >
> > ----------------------------------------------------------------
> > Chao Yu (1):
> >       raid5: fix to detect failure of register_shrinker
> >
> > Gayatri Kammela (5):
> >       lib/raid6: Add AVX512 optimized gen_syndrome functions
> >       lib/raid6: Add AVX512 optimized recovery functions
> >       lib/raid6/test/Makefile: Add avx512 gen_syndrome and recovery functions
> >       lib/raid6: Add AVX512 optimized xor_syndrome functions
> >       raid6/test/test.c: bug fix: Specify aligned(alignment) attributes to the char arrays
> >
> > Guoqing Jiang (9):
> >       md-cluster: call md_kick_rdev_from_array once ack failed
> >       md-cluster: use FORCEUNLOCK in lockres_free
> >       md-cluster: remove some unnecessary dlm_unlock_sync
> >       md: changes for MD_STILL_CLOSED flag
> >       md-cluster: clean related infos of cluster
> >       md-cluster: protect md_find_rdev_nr_rcu with rcu lock
> >       md-cluster: convert the completion to wait queue
> >       md-cluster: introduce dlm_lock_sync_interruptible to fix tasks hang
> >       md-cluster: make resync lock also could be interruptted
> >
> > Shaohua Li (5):
> >       raid5: allow arbitrary max_hw_sectors
> >       md/bitmap: fix wrong cleanup
> >       md: fix a potential deadlock
> >       raid5: handle register_shrinker failure
> >       md: set rotational bit
> >
> >  arch/x86/Makefile        |   5 +-
> >  drivers/md/bitmap.c      |   4 +-
> >  drivers/md/md-cluster.c  |  99 ++++++---
> >  drivers/md/md.c          |  44 +++-
> >  drivers/md/md.h          |   5 +-
> >  drivers/md/raid5.c       |  11 +-
> >  include/linux/raid/pq.h  |   4 +
> >  lib/raid6/Makefile       |   2 +-
> >  lib/raid6/algos.c        |  12 +
> >  lib/raid6/avx512.c       | 569 +++++++++++++++++++++++++++++++++++++++++++++++
> >  lib/raid6/recov_avx512.c | 388 ++++++++++++++++++++++++++++++++
> >  lib/raid6/test/Makefile  |   5 +-
> >  lib/raid6/test/test.c    |   7 +-
> >  lib/raid6/x86.h          |  10 +
> >  14 files changed, 1111 insertions(+), 54 deletions(-)
> >  create mode 100644 lib/raid6/avx512.c
> >  create mode 100644 lib/raid6/recov_avx512.c
> > --
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> 
> 
> 
> -- 
> Doug Dumitru
> EasyCo LLC