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authorChristoph Hellwig <hch@lst.de>2009-08-20 16:58:35 +0200
committerAnthony Liguori <aliguori@us.ibm.com>2009-08-27 20:30:22 -0500
commit5c6c3a6c54b23caa84fb4e046e85a461612279bb (patch)
tree7c23c2c86ca96f0a1b3dcbb86c70d5989e156710 /qemu-options.hx
parent9ef91a677110ec200d7b2904fc4bcae5a77329ad (diff)
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raw-posix: add Linux native AIO support
Now that do have a nicer interface to work against we can add Linux native AIO support. It's an extremly thing layer just setting up an iocb for the io_submit system call in the submission path, and registering an eventfd with the qemu poll handler to do complete the iocbs directly from there. This started out based on Anthony's earlier AIO patch, but after estimated 42,000 rewrites and just as many build system changes there's not much left of it. To enable native kernel aio use the aio=native sub-command on the drive command line. I have also added an option to qemu-io to test the aio support without needing a guest. Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
Diffstat (limited to 'qemu-options.hx')
-rw-r--r--qemu-options.hx4
1 files changed, 3 insertions, 1 deletions
diff --git a/qemu-options.hx b/qemu-options.hx
index e3bd314509..0c2b310562 100644
--- a/qemu-options.hx
+++ b/qemu-options.hx
@@ -95,7 +95,7 @@ DEF("drive", HAS_ARG, QEMU_OPTION_drive,
"-drive [file=file][,if=type][,bus=n][,unit=m][,media=d][,index=i]\n"
" [,cyls=c,heads=h,secs=s[,trans=t]][,snapshot=on|off]\n"
" [,cache=writethrough|writeback|none][,format=f][,serial=s]\n"
- " [,addr=A][,id=name]\n"
+ " [,addr=A][,id=name][,aio=threads|native]\n"
" use 'file' as a drive image\n")
DEF("set", HAS_ARG, QEMU_OPTION_set,
"-set group.id.arg=value\n"
@@ -128,6 +128,8 @@ These options have the same definition as they have in @option{-hdachs}.
@var{snapshot} is "on" or "off" and allows to enable snapshot for given drive (see @option{-snapshot}).
@item cache=@var{cache}
@var{cache} is "none", "writeback", or "writethrough" and controls how the host cache is used to access block data.
+@item aio=@var{aio}
+@var{aio} is "threads", or "native" and selects between pthread based disk I/O and native Linux AIO.
@item format=@var{format}
Specify which disk @var{format} will be used rather than detecting
the format. Can be used to specifiy format=raw to avoid interpreting