3a58934eb2
Use InitializeCriticalSectionAndSpinCount instead of IntializeCriticalSection. Using spin counts for critical sections of short duration enables the calling thread to avoid the wait operation in most situations which can dramatically improve the overall performance on multiprocessor systems. On Linux this change has no effect because the new winpr critical section implementation does not use the SpinCount field under Linux because the NPTL synchronization primitives are implemented using the extremely performant futex system calls which have this magic already built in. However, on Mac OS X this change improved the overall performance of the multithreaded RemoteFX decoder by 25 percent. I've used a SpinCount of 4000 which avoided 99 percent of the wait calls. This value is also used by Microsoft's heap manager for its per-heap critical sections. Note: This change requires pull request #1397 to be merged.
178 lines
3.5 KiB
C
178 lines
3.5 KiB
C
/**
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* WinPR: Windows Portable Runtime
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* Countdown Event
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*
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* Copyright 2012 Marc-Andre Moreau <marcandre.moreau@gmail.com>
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*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*/
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#ifdef HAVE_CONFIG_H
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#include "config.h"
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#endif
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#ifdef HAVE_UNISTD_H
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#include <unistd.h>
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#endif
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#include <winpr/crt.h>
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#include <winpr/collections.h>
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/**
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* C equivalent of the C# CountdownEvent Class
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* http://msdn.microsoft.com/en-us/library/dd235708/
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*/
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/**
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* Properties
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*/
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/**
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* Gets the number of remaining signals required to set the event.
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*/
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DWORD CountdownEvent_CurrentCount(wCountdownEvent* countdown)
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{
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return countdown->count;
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}
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/**
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* Gets the numbers of signals initially required to set the event.
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*/
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DWORD CountdownEvent_InitialCount(wCountdownEvent* countdown)
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{
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return countdown->initialCount;
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}
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/**
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* Determines whether the event is set.
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*/
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BOOL CountdownEvent_IsSet(wCountdownEvent* countdown)
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{
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BOOL status = FALSE;
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if (WaitForSingleObject(countdown->event, 0) == WAIT_OBJECT_0)
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status = TRUE;
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return status;
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}
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/**
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* Gets a WaitHandle that is used to wait for the event to be set.
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*/
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HANDLE CountdownEvent_WaitHandle(wCountdownEvent* countdown)
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{
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return countdown->event;
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}
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/**
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* Methods
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*/
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/**
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* Increments the CountdownEvent's current count by a specified value.
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*/
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void CountdownEvent_AddCount(wCountdownEvent* countdown, DWORD signalCount)
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{
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EnterCriticalSection(&countdown->lock);
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countdown->count += signalCount;
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if (countdown->count > 0)
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ResetEvent(countdown->event);
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LeaveCriticalSection(&countdown->lock);
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}
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/**
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* Registers multiple signals with the CountdownEvent, decrementing the value of CurrentCount by the specified amount.
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*/
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BOOL CountdownEvent_Signal(wCountdownEvent* countdown, DWORD signalCount)
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{
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BOOL status;
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BOOL newStatus;
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BOOL oldStatus;
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status = newStatus = oldStatus = FALSE;
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EnterCriticalSection(&countdown->lock);
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if (WaitForSingleObject(countdown->event, 0) == WAIT_OBJECT_0)
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oldStatus = TRUE;
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if (signalCount <= countdown->count)
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countdown->count -= signalCount;
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else
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countdown->count = 0;
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if (countdown->count == 0)
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newStatus = TRUE;
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if (newStatus && (!oldStatus))
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{
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SetEvent(countdown->event);
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status = TRUE;
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}
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LeaveCriticalSection(&countdown->lock);
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return status;
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}
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/**
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* Resets the InitialCount property to a specified value.
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*/
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void CountdownEvent_Reset(wCountdownEvent* countdown, DWORD count)
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{
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countdown->initialCount = count;
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}
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/**
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* Construction, Destruction
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*/
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wCountdownEvent* CountdownEvent_New(DWORD initialCount)
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{
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wCountdownEvent* countdown = NULL;
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countdown = (wCountdownEvent*) malloc(sizeof(wCountdownEvent));
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if (countdown)
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{
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countdown->count = initialCount;
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countdown->initialCount = initialCount;
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InitializeCriticalSectionAndSpinCount(&countdown->lock, 4000);
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countdown->event = CreateEvent(NULL, TRUE, FALSE, NULL);
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if (countdown->count == 0)
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SetEvent(countdown->event);
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}
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return countdown;
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}
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void CountdownEvent_Free(wCountdownEvent* countdown)
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{
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DeleteCriticalSection(&countdown->lock);
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CloseHandle(countdown->event);
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free(countdown);
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}
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