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  1. 12 11月, 2015 1 次提交
  3. 24 10月, 2015 2 次提交
  5. 16 10月, 2015 1 次提交
  7. 12 10月, 2015 1 次提交
  9. 02 10月, 2015 1 次提交
  11. 05 9月, 2015 1 次提交
    • M
      block/raw-posix: Use raw_normalize_devicepath() · bdd03cdf
      由 Max Reitz 提交于 
      The filename given to qemu_open() in block/raw-posix.c should generally
have been processed by raw_normalize_devicepath(); unless we are only
probing (in which case the caller often checks whether the file is a
block device or not, and this property will be changed by
raw_normalize_devicepath() on NetBSD) or it is about a deprecated device
(i.e. floppy).
Signed-off-by: NMax Reitz <mreitz@redhat.com>
Signed-off-by: NKevin Wolf <kwolf@redhat.com>
      bdd03cdf
  13. 07 7月, 2015 1 次提交
    • R
      block/raw-posix: Don't think /dev/fd/<NN> is a floppy drive. · 25d9747b
      由 Richard W.M. Jones 提交于 
      In libguestfs we use /dev/fd/<NN> to pass pre-opened file descriptors
to qemu-img.  Lately I've discovered that although this works, qemu
believes that these are floppy disk images.  That in itself isn't much
of a problem, but now qemu prints a warning about host floppy
pass-thru being deprecated.

Extend the existing test so that it ignores /dev/fd/ as well as
/dev/fdset/

A simple test of this, if you are using the bash shell, is:

  qemu-img info <( cat /dev/null )

without this patch:

  $ qemu-img info <( cat /dev/null )
  qemu-img: Host floppy pass-through is deprecated
  Support for it will be removed in a future release.
  qemu-img: Could not open '/dev/fd/63': Could not refresh total sector count: Illegal seek

with this patch:

  $ qemu-img info <( cat /dev/null )
  qemu-img: Could not open '/dev/fd/63': Could not refresh total sector count: Illegal seek
Signed-off-by: NRichard W.M. Jones <rjones@redhat.com>
Reviewed-by: NMarkus Armbruster <armbru@redhat.com>
Message-id: 1435761614-31358-1-git-send-email-rjones@redhat.com
Fixes: https://bugs.launchpad.net/qemu/+bug/1470536Signed-off-by: NStefan Hajnoczi <stefanha@redhat.com>
      25d9747b
  15. 23 6月, 2015 5 次提交
  17. 12 6月, 2015 2 次提交
  19. 22 5月, 2015 2 次提交
    • D
      block: align bounce buffers to page · 459b4e66
      由 Denis V. Lunev 提交于 
      The following sequence
    int fd = open(argv[1], O_RDWR | O_CREAT | O_DIRECT, 0644);
    for (i = 0; i < 100000; i++)
            write(fd, buf, 4096);
performs 5% better if buf is aligned to 4096 bytes.

The difference is quite reliable.

On the other hand we do not want at the moment to enforce bounce
buffering if guest request is aligned to 512 bytes.

The patch changes default bounce buffer optimal alignment to
MAX(page size, 4k). 4k is chosen as maximal known sector size on real
HDD.

The justification of the performance improve is quite interesting.
From the kernel point of view each request to the disk was split
by two. This could be seen by blktrace like this:
  9,0   11  1     0.000000000 11151  Q  WS 312737792 + 1023 [qemu-img]
  9,0   11  2     0.000007938 11151  Q  WS 312738815 + 8 [qemu-img]
  9,0   11  3     0.000030735 11151  Q  WS 312738823 + 1016 [qemu-img]
  9,0   11  4     0.000032482 11151  Q  WS 312739839 + 8 [qemu-img]
  9,0   11  5     0.000041379 11151  Q  WS 312739847 + 1016 [qemu-img]
  9,0   11  6     0.000042818 11151  Q  WS 312740863 + 8 [qemu-img]
  9,0   11  7     0.000051236 11151  Q  WS 312740871 + 1017 [qemu-img]
  9,0    5  1     0.169071519 11151  Q  WS 312741888 + 1023 [qemu-img]
After the patch the pattern becomes normal:
  9,0    6  1     0.000000000 12422  Q  WS 314834944 + 1024 [qemu-img]
  9,0    6  2     0.000038527 12422  Q  WS 314835968 + 1024 [qemu-img]
  9,0    6  3     0.000072849 12422  Q  WS 314836992 + 1024 [qemu-img]
  9,0    6  4     0.000106276 12422  Q  WS 314838016 + 1024 [qemu-img]
and the amount of requests sent to disk (could be calculated counting
number of lines in the output of blktrace) is reduced about 2 times.

Both qemu-img and qemu-io are affected while qemu-kvm is not. The guest
does his job well and real requests comes properly aligned (to page).
Signed-off-by: NDenis V. Lunev <den@openvz.org>
Reviewed-by: NKevin Wolf <kwolf@redhat.com>
Message-id: 1431441056-26198-3-git-send-email-den@openvz.org
CC: Paolo Bonzini <pbonzini@redhat.com>
CC: Kevin Wolf <kwolf@redhat.com>
CC: Stefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: NStefan Hajnoczi <stefanha@redhat.com>
      459b4e66
    • D
      block: minimal bounce buffer alignment · 4196d2f0
      由 Denis V. Lunev 提交于 
      The patch introduces new concept: minimal memory alignment for bounce
buffers. Original so called "optimal" value is actually minimal required
value for aligment. It should be used for validation that the IOVec
is properly aligned and bounce buffer is not required.

Though, from the performance point of view, it would be better if
bounce buffer or IOVec allocated by QEMU will be aligned stricter.

The patch does not change any alignment value yet.
Signed-off-by: NDenis V. Lunev <den@openvz.org>
Reviewed-by: NKevin Wolf <kwolf@redhat.com>
Message-id: 1431441056-26198-2-git-send-email-den@openvz.org
CC: Paolo Bonzini <pbonzini@redhat.com>
Reviewed-by: NKevin Wolf <kwolf@redhat.com>
CC: Stefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: NStefan Hajnoczi <stefanha@redhat.com>
      4196d2f0
  21. 19 3月, 2015 2 次提交
  23. 10 3月, 2015 3 次提交
  25. 09 3月, 2015 1 次提交
    • D
      block/raw-posix: fix compilation warning on OSX · a6dcf097
      由 Denis V. Lunev 提交于 
      block/raw-posix.c:947:19: warning: unused variable 's' [-Wunused-variable]
    BDRVRawState *s = aiocb->bs->opaque;

This variable is used only when on of the following macros are defined
CONFIG_XFS, CONFIG_FALLOCATE, CONFIG_FALLOCATE_PUNCH_HOLE or
CONFIG_FALLOCATE_ZERO_RANGE. Fortunately, CONFIG_FALLOCATE_PUNCH_HOLE
and CONFIG_FALLOCATE_ZERO_RANGE could be defined only along with
CONFIG_FALLOCATE. Therefore checking for CONFIG_XFS or CONFIG_FALLOCATE
would be enough.
Signed-off-by: NDenis V. Lunev <den@openvz.org>
CC: Peter Maydell <peter.maydell@linaro.org>
CC: Kevin Wolf <kwolf@redhat.com>
Signed-off-by: NKevin Wolf <kwolf@redhat.com>
      a6dcf097
  27. 16 2月, 2015 1 次提交
  29. 07 2月, 2015 7 次提交
  31. 10 12月, 2014 3 次提交
  33. 18 11月, 2014 6 次提交