Re: [Qemu-devel] [patch] non-blocking disk IO

[John Coiner <jcoiner@stanfordalumni.org>]

Whoops. I had the mistaken belief that Qemu already used pthreads.

So, the makefiles and configure script need to handle pthreads somehow 
(especially on windows.) Pthreads-w32 is refusing to 'make install' 
itself into standard lib and include directories. Unlike SDL, there is 
no 'pthread-config' to tell us where it lives.

Suppose that on Windows, we tell people to unpack the pthread 
distribution within the qemu tree. Qemu's configure script could find 
it, build a static pthread library, and link that into Qemu.

This removes the need for the user to:
  * read pthreads-w32 documents,
  * issue a separate build command for pthreads-w32,
  * get confused before realizing that pthreads-w32 doesn't really 
support 'make install',
  * hack at qemu until it points to the uninstalled pthreads dir,
  * copy the pthreads DLL into c:\windows

I'll look at adding this to the configure script.

-john



Christian MICHON wrote:
> I managed to make it work (qemu+non blocking IO on windows host),
> with a rough estimation of 10% speed increase at the early stage of
> windows setup. I expect more once windows installs itself in true
> multitasking mode. :)
> 
> What you need to do is:
> - download pthreads-w32-2-6-0-release.tar.gz and compile it from scratch
>  (make clean GC)
> - you also need to add the following lines inside block.c (usleep is not
> present in win32/mingw32)
> 
>  #ifdef WIN32
> void usleep(unsigned long usec)
> {
>     Sleep(usec/1000);
> }
> #endif
> 
> - you need to update the link to include "-lpthreadGC2 -lz", and
> keep a copy of the pthreadGC2.dll where qemu.exe will be
> (to pu it just in from of "-lz" is just my personal suggestion)
> 
> HIH,
> Christian
> 
> On 10/3/05, Elefterios Stamatogiannakis <estama@dblab.ece.ntua.gr> wrote:
> 
>>With which pthreads library have you compiled it under windows?
>>
>>I've tried it with the one here:
>>
>>ftp://sources.redhat.com/pub/pthreads-win32/
>>
>>but it didn't compile.
>>
>>teris.
> 
> 
> 
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