Hello I have some question about asynchronous i/o in QEMU block driver: Why a file format with asynchronous i/o support(ex. qcow) doesn't need to register bdrv_read/bdrv_write which is registered in vhd file format?? Would qcow block driver also support synchronous i/o??
thanks a lot Mitnick 2011/4/2 Kevin Wolf <kw...@redhat.com> > Am 01.04.2011 17:15, schrieb Lyu Mitnick: > > Hello Stefan > > > > Hello Mitnick, > > > > asynchronous i/o is also missing in block/vpc.c. > > > > All newer block drivers support asynchronous reads and writes, > > only some old drivers don't. > > > > So adding asynchronous i/o to at least some of the old drivers > > would improve their usability. > > > > Look for "aio" in block/*.c to get a starting point. > > > > Regards > > Stefan (W.) > > > > > > I look for "aio" in block/*.c as a starting point of asynchronous i/o. > > And I > > found that there isn't any "aio" keywords in block/vmdk.c. block/vmdk.c > > is used as block driver for the VMDK format. Is it means that > asynchronous > > i/o is also missing in VMDK format? > > Yes, the VMDK implementation is completely synchronous. > > Kevin >
