Fennel: DeviceAccessScheduler Class Reference

DeviceAccessScheduler::~DeviceAccessScheduler ( ) [virtual]

Definition at line 115 of file DeviceAccessScheduler.cpp.

00116 {
00117 }

DeviceAccessScheduler * DeviceAccessScheduler::newScheduler ( DeviceAccessSchedulerParams const & params ) [static]

Creates a scheduler.

Parameters:

params

DeviceAccessSchedulerParams to use

Returns:: new scheduler; caller is responsible for deleting it

Definition at line 70 of file DeviceAccessScheduler.cpp.

References DeviceAccessSchedulerParams::AIO_LINUX_SCHEDULER, DeviceAccessSchedulerParams::AIO_POLLING_SCHEDULER, DeviceAccessSchedulerParams::AIO_SIGNAL_SCHEDULER, dlopenAioLinuxScheduler(), DeviceAccessSchedulerParams::IO_COMPLETION_PORT_SCHEDULER, DeviceAccessSchedulerParams::schedulerType, DeviceAccessSchedulerParams::THREAD_POOL_SCHEDULER, and DeviceAccessSchedulerParams::usingDefaultSchedulerType.

Referenced by CacheImpl< PageT, VictimPolicyT >::CacheImpl(), and RandomAccessFileDeviceTest::testAsyncIOImpl().

00072 {
00073     switch (params.schedulerType) {
00074     case DeviceAccessSchedulerParams::THREAD_POOL_SCHEDULER:
00075         return new ThreadPoolScheduler(params);
00076 
00077 #ifdef __MSVC__
00078     case DeviceAccessSchedulerParams::IO_COMPLETION_PORT_SCHEDULER:
00079         return new IoCompletionPortScheduler(params);
00080 #endif
00081 
00082 #ifdef USE_LIBAIO_H
00083     case DeviceAccessSchedulerParams::AIO_LINUX_SCHEDULER:
00084         {
00085             DeviceAccessScheduler *pScheduler = dlopenAioLinuxScheduler(params);
00086             if (pScheduler) {
00087                 return pScheduler;
00088             } else {
00089                 // if the aioLinux scheduler was explicitly selected (vs simply
00090                 // using the default type for the OS), then the AIO runtime
00091                 // library must be installed; otherwise, fall through to use
00092                 // ThreadPoolScheduler as fallback
00093                 if (params.usingDefaultSchedulerType) {
00094                     break;
00095                 }
00096                 throw FennelExcn(FennelResource::instance().libaioRequired());
00097             }
00098         }
00099 #endif
00100 
00101 #ifdef USE_AIO_H
00102     case DeviceAccessSchedulerParams::AIO_POLLING_SCHEDULER:
00103         return new AioPollingScheduler(params);
00104     case DeviceAccessSchedulerParams::AIO_SIGNAL_SCHEDULER:
00105         return new AioSignalScheduler(params);
00106 #endif
00107 
00108     default:
00109         // fall through to use ThreadPoolScheduler as a fallback
00110         break;
00111     }
00112     return new ThreadPoolScheduler(params);
00113 }

void DeviceAccessScheduler::registerDevice ( SharedRandomAccessDevice pDevice ) [virtual]

Registers a device for which this scheduler will process requests.

The default implementation does nothing.

Parameters:

pDevice

device to be registered

Reimplemented in AioLinuxScheduler, and IoCompletionPortScheduler.

Definition at line 142 of file DeviceAccessScheduler.cpp.

Referenced by RandomAccessFileDeviceTest::testAsyncIOImpl().

00144 {
00145 }

void DeviceAccessScheduler::unregisterDevice ( SharedRandomAccessDevice pDevice ) [virtual]

Unregisters a device.

The default implementation does nothing.

Parameters:

pDevice

device to be unregistered

Definition at line 147 of file DeviceAccessScheduler.cpp.

Referenced by RandomAccessFileDeviceTest::testAsyncIOImpl().

00149 {
00150 }

virtual bool DeviceAccessScheduler::schedule ( RandomAccessRequest & request ) [pure virtual]

Initiates a request, the details of which must already have been defined by the caller.

When the request completes, this scheduler will call notifyTransferCompletion on each binding associated with the request, and also break up the binding list. The bindings must not be altered by the caller until this notification is received. However, the request parameter itself need not live beyond this call.

Care must be taken to ensure that the schedule/notify sequences cannot deadlock. For example, the caller of schedule may hold a lock on a binding, and the implementation of schedule may acquire a scheduler lock internally. The notification callback may also need to take a lock on the binding. Thus, it is important that no scheduler lock be held while notifyTransferCompletion is called.

Parameters:

request

parameters for the request to be scheduled

Returns:: true if the request was successfully scheduled without any retries

Implemented in AioLinuxScheduler, AioPollingScheduler, AioSignalScheduler, IoCompletionPortScheduler, and ThreadPoolScheduler.

Referenced by SegPageBackupRestoreDevice::backupPage(), CacheImpl< PageT, VictimPolicyT >::prefetchBatch(), SegPageBackupRestoreDevice::restorePage(), and RandomAccessFileDeviceTest::testAsyncIOImpl().

virtual void DeviceAccessScheduler::stop ( ) [pure virtual]

Shuts down, waiting for all pending requests to complete.

Implemented in AioLinuxScheduler, AioPollingScheduler, AioSignalScheduler, IoCompletionPortScheduler, and ThreadPoolScheduler.

Referenced by CacheImpl< PageT, VictimPolicyT >::closeImpl(), and RandomAccessFileDeviceTest::testAsyncIOImpl().

DeviceAccessScheduler Class Reference

Public Member Functions

Static Public Member Functions

Detailed Description

Constructor & Destructor Documentation

Member Function Documentation


Public Member Functions
virtual	~DeviceAccessScheduler ()
virtual void	registerDevice (SharedRandomAccessDevice pDevice)
	Registers a device for which this scheduler will process requests.
virtual void	unregisterDevice (SharedRandomAccessDevice pDevice)
	Unregisters a device.
virtual bool	schedule (RandomAccessRequest &request)=0
	Initiates a request, the details of which must already have been defined by the caller.
virtual void	stop ()=0
	Shuts down, waiting for all pending requests to complete.
Static Public Member Functions
static DeviceAccessScheduler *	newScheduler (DeviceAccessSchedulerParams const &params)
	Creates a scheduler.