High cpu load while using OpenMP

Question

Following code results in 100% cpu load though it really does nothing (only sleeps).
Compiled with VS2008 SP1 with option "/openmp".
Processor Core 2 Duo with XP SP3.

I can see in the debugger that high cpu load occurs in VCOMP90!_vcomp::PartialBarrier1_Poll::Block function. It seems to have a tight loop calling Sleep(0) that results in hight cpu load and high "System Calls/sec" rate.

ntdll!KiFastSystemCallRet
ntdll!NtDelayExecution+0xc
kernel32!SleepEx+0x61
kernel32!Sleep+0xf
VCOMP90!_vcomp::PartialBarrier1_Poll::Block+0x20 [f:\dd\vctools\openmprt\inc\synch.h @ 47]
VCOMP90!InvokeThreadTeam+0x74 [f:\dd\vctools\openmprt\src\ttpool.cpp @ 608]
VCOMP90!_vcomp_fork+0x136 [f:\dd\vctools\openmprt\src\fork.cpp @ 186]
test_omp!TestFunc+0x15
test_omp!main+0x5
test_omp!__tmainCRTStartup+0x10f [f:\dd\vctools\crt_bld\self_x86\crt\src\crtexe.c @ 586]
kernel32!BaseProcessStart+0x23


_____________________________________

#include <windows.h>
#include <omp.h>

void TestFunc();

int main()
{
    TestFunc();
    return 0;
};


void InForCall(int);


void TestFunc()
{
#pragma omp parallel for num_threads(3)
    for(int i = 0; i < 3; ++i)
    {
        switch(i)
        {
        case 0:
            InForCall(i);
            break;
        case 1:
            InForCall(i);
            break;
        case 2:
            InForCall(i);
            break;
        };       
    };
};

void InForCall(int i)
{
    Sleep(1000 + i*5000);
};