[Bug 35587] League of Legends: Long delay before loading into the game when sound is enabled

http://bugs.winehq.org/show_bug.cgi?id=35587

--- Comment #24 from Riccardo  ---
(In reply to Riccardo from comment #23)
> (In reply to Riccardo from comment #22)
> > (In reply to Dmitry Timoshkov from comment #21)
> > > (In reply to Riccardo from comment #20)
> > > > sample run:
> > > > - windows xp sp3:
> > > >
> > > > Large read: 15 for 11128460 bytes - overlapped: 0
> > > > Small reads: 14500 for 11128460 bytes - overlapped (total: 2782115): 2782115
> > > > - wine 1.7.16 ubuntu 14.04 x64 kernel 3.13.0-24-generic:
> > > >
> > > > Large read: 15 for 11128460 bytes - overlapped: 0
> > > > Small reads: 44849 for 11128460 bytes - overlapped (total: 2782115): 0
> > >
> > > It would be interesting to compare this to a not overlapped case, which
> > > I suspect will show the same results.
> >
> > Hello Dmitry, you're right, without FLAG_FILE_OVERLAPPED the results are
> > more or less the same for both Windows and wine.
>
> It looks like this issue is actually two different issues:
> - Commenting out (or, actually, disabling for type=FD_TYPE_FILE)
>
> send_completion in ntdll/file.c NtReadFile brings down my test case
> execution time from 55s to 5s in wine. See relevant line:
>   if (send_completion) NTDLL_AddCompletion( hFile, cvalue, status, total );
> - The fact that we're not doing overlapped IO locks the game UI for a while
>
> during load
>
> game load time:
> - with send_completion: ~120s to load
> - without send_completion: ~105s to load
>
> I think the game issue is a mixture of those two: the game may crash for
> slow systems because it might remain "locked" for a while (no overlapped
> IO)..and it's even a bit slower than it should because of the
> NTDLL_AddCompletion call.

I tricked the game, in dlls/kernel32/file.c NtReadFile add:

if (status != STATUS_PENDING && bytesRead) {
        *bytesRead = io_status->Information;
+        if (cvalue) {
+            // http://support.microsoft.com/kb/156932?ln=en-us
+            // even if we did a sync read tell the client we didn't so it can
process its events
+            SetLastError( RtlNtStatusToDosError(STATUS_PENDING) );
+            return FALSE;
+        }
    }

this will cause the user to call GetOverlappedResult in order to get the data
(and theoretically execute something in background meanwhile).

25532.065:trace:file:ReadFile 0xe4 0x33c5e8 4 0x33c440 0x3e11650
25532.065:trace:file:GetOverlappedResult (0xe4 0x3e11650 0x33c444 0)

as you can see from this snippet of a new trace the trick works.

However loading time or UI responsivity are not improved at all and I think the
conclusion here is that this is not a bug in wine.

The game should really read more than 4 bytes per call...

As for the NTDLL_AddCompletion slowness, since I doubt anything is doing 2M
calls for a single file, I wouldn't just mind about it.