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  1. 25 2月, 2009 1 次提交
    • S
      x86: fix performance regression in write() syscall · 30d697fa
      由 Salman Qazi 提交于 
      While the introduction of __copy_from_user_nocache (see commit:
0812a579) may have been an improvement
for sufficiently large writes, there is evidence to show that it is
deterimental for small writes.  Unixbench's fstime test gives the
following results for 256 byte writes with MAX_BLOCK of 2000:

    2.6.29-rc6 ( 5 samples, each in KB/sec ):
    283750, 295200, 294500, 293000, 293300

    2.6.29-rc6 + this patch (5 samples, each in KB/sec):
    313050, 3106750, 293350, 306300, 307900

    2.6.18
    395700, 342000, 399100, 366050, 359850

    See w_test() in src/fstime.c in unixbench version 4.1.0.  Basically, the above test
    consists of counting how much we can write in this manner:

    alarm(10);
    while (!sigalarm) {
            for (f_blocks = 0; f_blocks < 2000; ++f_blocks) {
                   write(f, buf, 256);
            }
            lseek(f, 0L, 0);
    }

Note, there are other components to the write syscall regression
that are not addressed here.
Signed-off-by: NSalman Qazi <sqazi@google.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: NIngo Molnar <mingo@elte.hu>
      30d697fa
  3. 19 11月, 2008 1 次提交
  5. 23 10月, 2008 2 次提交
  7. 03 10月, 2008 1 次提交
  9. 11 9月, 2008 1 次提交
  11. 10 9月, 2008 1 次提交
    • N
      x86: some lock annotations for user copy paths · c10d38dd
      由 Nick Piggin 提交于 
      copy_to/from_user and all its variants (except the atomic ones) can take a
page fault and perform non-trivial work like taking mmap_sem and entering
the filesyste/pagecache.

Unfortunately, this often escapes lockdep because a common pattern is to
use it to read in some arguments just set up from userspace, or write data
back to a hot buffer. In those cases, it will be unlikely for page reclaim
to get a window in to cause copy_*_user to fault.

With the new might_lock primitives, add some annotations to x86. I don't
know if I caught all possible faulting points (it's a bit of a maze, and I
didn't really look at 32-bit). But this is a starting point.

Boots and runs OK so far.
Signed-off-by: NNick Piggin <npiggin@suse.de>
Acked-by: NPeter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: NIngo Molnar <mingo@elte.hu>
      c10d38dd
  13. 23 7月, 2008 1 次提交
    • V
      x86: consolidate header guards · 77ef50a5
      由 Vegard Nossum 提交于 
      This patch is the result of an automatic script that consolidates the
format of all the headers in include/asm-x86/.

The format:

1. No leading underscore. Names with leading underscores are reserved.
2. Pathname components are separated by two underscores. So we can
   distinguish between mm_types.h and mm/types.h.
3. Everything except letters and numbers are turned into single
   underscores.
Signed-off-by: NVegard Nossum <vegard.nossum@gmail.com>
      77ef50a5
  15. 09 7月, 2008 19 次提交
  17. 17 4月, 2008 1 次提交
  19. 04 2月, 2008 1 次提交
  21. 30 1月, 2008 1 次提交
  23. 11 10月, 2007 1 次提交
  25. 27 7月, 2007 1 次提交
  27. 15 3月, 2007 1 次提交
  29. 13 2月, 2007 1 次提交
    • A
      [PATCH] x86-64: Add __copy_from_user_nocache · 0812a579
      由 Andi Kleen 提交于 
      This does user copies in fs write() into the page cache with write combining.
This pushes the destination out of the CPU's cache, but allows higher bandwidth
in some case.

The theory is that the page cache data is usually not touched by the
CPU again and it's better to not pollute the cache with it. Also it is a little
faster.
Signed-off-by: NAndi Kleen <ak@suse.de>
      0812a579
  31. 12 2月, 2007 1 次提交
  33. 26 1月, 2007 1 次提交
  35. 04 12月, 2006 1 次提交
  37. 30 9月, 2006 1 次提交
  39. 26 9月, 2006 2 次提交