On Sun, Dec 30, 2012 at 12:02:34AM +0400, Nikolay Sivov wrote:
On 12/29/2012 23:04, Marcus Meissner wrote:
From: Marcus Meissner <marcus@jet.(none)>
Modeled pretty much after the implementation described in glibc/nptl/DESIGN-condvar.txt with its futex usage sofar replaced by regular Win32 Semaphores.
An additional futex implementation is possible.
I *think* I have the semantics correct, there is 1 small place where it might have unnecessary CPU usage though.
Ciao, Marcus
+/**********************************************************************
InitializeConditionVariable (KERNEL32.@)- */
+VOID WINAPI InitializeConditionVariable(PCONDITION_VARIABLE variable) +{
- struct _condition_var_intern *var;
- variable->Ptr = HeapAlloc(GetProcessHeap(),HEAP_ZERO_MEMORY,sizeof(struct _condition_var_intern));
- var = variable->Ptr;
- if (!var) return;
- InitializeCriticalSection (&var->crit);
- var->crit.DebugInfo->Spare[0] = (DWORD_PTR)(__FILE__ ": ConditionVariable.cs");
+}
I don't think it allocates anything at all, what makes me believe that is that stuff like CONDITION_VARIABLE_INIT exists. After googling a bit for it I see that gallium from mesa has some platform dependent stuff in code that uses this API like that:
+#define pipe_static_condvar(cond) \
- /*static*/ pipe_condvar cond = CONDITION_VARIABLE_INIT
So this structure has nothing more than a single pointer value, value 0 of it means it's initialized. I think you could just add some tests to see if it's really reset to 0 from initial value.
I am not fully sure. The SDK only has "PVOID Ptr" and that alone is not enough space to implement conditional variables.
CONDITION_VARIABLE_INIT is only there to init it to NULL. (if you look at the SDK CONDITION_VARIABLE_INIT seems to be {0} )
So I suspect some private data structure is hidden into it.
I however do not know if windows allocates it from heap or from where exactly.
Also regarding tests I don't think randomizing timeouts is a good idea cause it adds some unpredictable behaviour and it's not really clear if we could rely on such tests results.
I have to think about those some more :/
I testing Adobe Lightroom 4 with the patch I encountered more conditions I should probably also test for.
Ciao, Marcus