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improvement to os_cpu_SetThreadAffinityMask: avoid Sleep(), fall back to APIC ID if GetCurrentProcessorNumber is unavailable

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This was SVN commit r7841.
This commit is contained in:
janwas 2010-08-02 07:56:37 +00:00
parent 76e6b6dbe3
commit 95047013d0
1 changed files with 21 additions and 20 deletions
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41
source/lib/sysdep/os/win/wcpu.cpp
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@ -31,6 +31,8 @@
#include "lib/bits.h"
#include "lib/module_init.h"
#include "lib/sysdep/os/win/wutil.h"
#include "lib/sysdep/arch/x86_x64/x86_x64.h"
#include "lib/sysdep/arch/x86_x64/topology.h"
#ifdef _OPENMP
# include <omp.h>
@ -231,25 +233,30 @@ uintptr_t wcpu_ProcessorMaskFromAffinity(DWORD_PTR processAffinity, DWORD_PTR af
}
static const DWORD invalidProcessorNumber = (DWORD)-1;
//-----------------------------------------------------------------------------
static DWORD CurrentProcessorNumber()
static void VerifyRunningOnCorrectProcessors(DWORD_PTR affinity)
{
// note: we don't need to expose this to callers because the
// higher-level code ensures processor == omp_get_thread_num().
DWORD currentProcessor;
// note: NtGetCurrentProcessorNumber and RtlGetCurrentProcessorNumber aren't
// implemented on WinXP SP2.
WUTIL_FUNC(pGetCurrentProcessorNumber, DWORD, (void));
WUTIL_IMPORT_KERNEL32(GetCurrentProcessorNumber, pGetCurrentProcessorNumber);
if(pGetCurrentProcessorNumber)
return pGetCurrentProcessorNumber();
currentProcessor = pGetCurrentProcessorNumber();
else
{
// note: we won't bother mapping APIC IDs to processor numbers or
// using LSL to re-implement GetCurrentProcessorNumber because
// this routine is just a debug aid.
return invalidProcessorNumber;
const u8* apicIds = ApicIds();
const u8* end = apicIds+os_cpu_NumProcessors();
const u8* it = std::find(apicIds, end, x86_x64_ApicId());
debug_assert(it != end);
currentProcessor = it - apicIds;
}
debug_assert(IsBitSet(affinity, currentProcessor));
}
@ -259,20 +266,14 @@ uintptr_t os_cpu_SetThreadAffinityMask(uintptr_t processorMask)
DWORD_PTR processAffinity, systemAffinity;
const BOOL ok = GetProcessAffinityMask(GetCurrentProcess(), &processAffinity, &systemAffinity);
debug_assert(ok);
WARN_IF_FALSE(ok);
const DWORD_PTR affinity = wcpu_AffinityFromProcessorMask(processAffinity, processorMask);
const DWORD_PTR previousAffinity = SetThreadAffinityMask(GetCurrentThread(), affinity);
debug_assert(previousAffinity != 0); // ensure function didn't fail
// hopefully reschedule our thread
Sleep(0);
// verify we're running on the correct processor
const DWORD currentProcessorNumber = CurrentProcessorNumber();
if(currentProcessorNumber != invalidProcessorNumber)
debug_assert(IsBitSet(affinity, currentProcessorNumber));
// (MSDN says SetThreadAffinityMask takes care of rescheduling)
VerifyRunningOnCorrectProcessors(affinity);
const uintptr_t previousProcessorMask = wcpu_ProcessorMaskFromAffinity(processAffinity, previousAffinity);
return previousProcessorMask;
}
@ -284,7 +285,7 @@ LibError os_cpu_CallByEachCPU(OsCpuCallback cb, uintptr_t cbData)
DWORD_PTR processAffinity, systemAffinity;
{
const BOOL ok = GetProcessAffinityMask(GetCurrentProcess(), &processAffinity, &systemAffinity);
debug_assert(ok);
WARN_IF_FALSE(ok);
if(processAffinity != systemAffinity)
return ERR::OS_CPU_RESTRICTED_AFFINITY; // NOWARN
}