> Clemens Kolbitsch wrote: > > hi everyone! > > i have a strange problem (at least to me it seems strange :-) ): > > > > i have implemented a pci device (Network IC) and it works just fine when > > using a standard image. however i now want to support snapshotting... > > > > i started to convert my image into the qcow2 format and suddenly my code > > does not work any more... even if i uncomment everything that has to do > > with snapshotting in my code, it still blocks during qemu startup. > > > > the thing that could cause this: i use 2 additional threads in my NIC > > code ... each is working with semaphores that might cause problems. > > > > is there something in particular i have to be careful of when using qcow2 > > file format? > > > > thanks!! > > Qcow2 uses async io which triggers io completion with SIGIO signal. > If you use threads you must mask this (and also SIGALARM, ..) so your > thread won't > take over the main threads handling. > Anyway, using threads is not the standard qemu guideline.
Hi, Ok.. thanks! How do I tell Qemu that I use threads (in this case I don't see an easy way around using them... although there is one obviously ;-) )?? In what other HW example can I see how to use the SIGIO completion stuff? Clemens
