Speeding up wineserver (again)
wine at troy.rollo.name
Mon Jul 7 21:27:52 CDT 2003
I've been looking at the various efforts over the years to speed up wineserver
or eliminate it altogether (by substituting a kernel service). Certainly the
current degree of reliance on a separate process that is scheduled according
to the operating system's own priorities creates significant speed problems.
Some of this migh be alleviated by boosting the priority of the wineserver
process or by making it a real time task, but there are still some operations
it appears to be performing some operations that result in a yield and hence
subject it to another wait in the queue for at least one time slice.
Even if the wineserver itself could be sped up in this way, individual
processes would stull be subjected to time waiting in the queue after they
make a request of wineserver. The problem becomes more severe on a heavily
The approaches suggested so far:
Suffers from reliability problems which may allow one
process to put the system in an inconsistent state.
The only effort so far seemed to put way too much
into the kernel, and was abandoned over two years
Other possible approaches that I haven't seen directly discussed on the
An exokernel using the x86 multiring capability
Not portable to non-x86 architectures.
Also referred to under other names. This mechanism would
allow one process to call into another process without
giving up part of its time slice. Would require modifications
to the kernel's scheduler and to standard kernel data
structures, hence would have to be considered "rude". It
would have one advantage in that the interface
differences between this mechanism and the current
mechanism could be transparent.
Have I missed any?
Anyway, I'm thinking that perhaps the kernel module approach was the right
basic approach, but that the particular attempt made was merely too broad. A
better approach would be to define a set of kernel calls that could be used
to implement all of the other stuff (and there are currently 176 types of
wineserver request, so I haven't taken the time to see if I've covered them
all yet) in an in-process library.
Transparency substitution for wineserver would, I guess, be achieved by having
the kernel module and its supporting library implement the wineserver
requests using the wineserver data structures, and perhaps having wineserver
use a non-kernel version of these facilities.
The following are things I could see immediately would be part of the kernel
winekernel_attach_to_kernel(char const *kernid);
char const *name,
void const *data,
char const *name);
There would be other things that would be in the "nice to have" category too
(I'm thinking specifically about path name translation being done in a way
that requires less seeks through the file system).
The way I see this working is that Wine kernel objects are stored (strangely
enough) in kernel memory. This effectively amounts to a shared memory
approach but with the kernel module able to clean up after a misbehaving
process. In the event that cleanups after a misbehaving process were to be
too complex, there would still be room for a server process that does this,
and the kernel could simply assign ownership of the objects from the bad
process to the server process, which gets notified via another set of calls
when it receives the objects. The object name would be of the form
"namespace:name", so as to have:
A process could allow the kernel to assign the name within the namespace, so
that, for example:
obj = winekernel_object_create("window", windowdata, windowdata_size);
winekernel_object_gername(obj, achHWND, 15);
The idea behind the "wine_attach_to_kernel" call would be to allow for the
kernel to serve either multiple different users or multiple different Windows
operating system types without the objects from all of them being
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