Linux与Windows的设备驱动差异比较课件

1、A Comparative Study of the Linux and Windows Device Driver Architectures with a focus on IEEE1394 (high speed serial bus) driversMelekam Tsegayeg98t4414campus.ru.ac.zaSupervisors Prof. Richard Foss, Bradley KlinkradtOverviewThe Linux and Windows driver architecturesThe Linux and Windows IEEE 1394 dr

2、iver stacksDriver development on the two platformsResults of the studyWhy the study was conducted ?Microsoft Windows and Linux Two of the most popular operating systemsNo previous comparisons of their driver architectures done by other researchersIEEE 1394 (firewire)Popular bus offering high data tr

3、ansfer ratesActive research area for the CS departments Audio Engineering GroupIEEE 1394Data Transfer rates of 100, 200 and 400 MbpsIsochronous mode of transferGuaranteed bandwidth (80%)Asynchronous mode of transferGuaranteed packet delivery (20% or more) Fully plug n playIEEE 1394 Consumer Products

4、Device DriversA driver is a piece of software that extends a kernels functionality Drivers enable applications (through the kernel)to transfer data to and from a deviceto control the a device to allow modification of its attributesComposed of a set of routines that a kernel calls at appropriate time

5、s e.g. read/writeTypical driver routinesA driver would implementInitialisationCleanupOpenReadWriteI/O Control (ioctl)CloseThe Windows driver architectureStandard model The Windows Driver Model (WDM)bus, functional & filter driversPnP & Power managementCommunication I/O request packets (IRPs)The Linu

6、x driver architectureNo standard driver model Drivers are modulesNo PnP & Power management message dispatchingCommunication through direct function callsSide by side comparison of the two driver architecturesLinuxWindowsIEEE 1394 driver stacksThe Windows IEEE 1394 stack closed sourcemaintained by Mi

7、crosoftstableThe Linux IEEE 1394 stack open sourcemaintained by the Linux 1394 community (private individuals)tagged experimentalThe Windows IEEE 1394 stackHost controllerBus driverClient driversCommunication I/O request block (IRB)The Linux IEEE 1394 stackHost controllerBus driversClient driversCom

8、municationdirect function callsDirect driver possibleSide by side comparison of the two IEEE 1394 stacksLinuxWindowsThe Windows IEEE 1394 implementationThe Linux IEEE 1394 implementationWhat operations should IEEE 1394 client drivers provide ?Asynchronous OperationsReadWriteLockListenRegister Asynch

9、ronous ListeningDeregister Asynchronous ListeningIsochronous operationsListenTalkAsynchronous streamingWhat operations should IEEE 1394 client drivers provide ? (Continued)Bus reset handlingRegister Bus Reset HandlerGenerate Soft Bus ResetObtain Bus Information (e.g. node count)Local configuration R

10、OM manipulationNetwork troubleshooting Pinging of nodes Device Driver Development EnvironmentsIssues to be considered when creating driversMemory managementThe kernel provides memory allocation/de-allocation routinesHas two pools of memory (swappable, non-swappable)Data structuresThe kernel provides

11、 implementations for queues, lists, stacksSynchronisation with spin locks, mutexes, semaphores, signal objectsIssues to be considered when creating drivers (Continued)Drivers routines must be re-entrant i.e. should be executable by multiple threads with no problemsavoid recursionHardware Abstraction

12、 Layeruse HAL routines provided by the kernel to access hardwareMap of software produced during this studyWindows raw1394 driverLinux raw1394-2 driverLinux Ieee1394diagDriver TestsTests were run to determinehighest data transfer rates that can be achieved by each of the IEEE 1394 drivershow close th

13、ese came to the theoretical maximum of 50MB/sBus analyser used to measure the duration of data transfers the amount of data transferredCalculated the data transfer rate in MB/sTest resultsIsochronous mode Windows raw13948.9 MB/s packet size 1024 bytesLinux raw13944.5 MB/s packet size 512 bytesIsochr

14、onous mode (buffered)Linux raw1394-28.9 MB/s packet size 1024 bytesWindows raw139417.7 MB/spacket size 2048 bytesTest results (continued)Drivers from both Linux and Windows do not transfer data at a rate close to the theoretical 50MB/sThey achieve almost half that due to the PCI bus bottleneck (theo

15、retical 132MB/s) In practice have that availableshared by all I/O devices attached to the PCI busThe PCI bus has latency problemsdriver implementation may not be efficientConclusionA comparison of the Windows and Linux driver architectures has shown thatDrivers for the two platform have similar comp

16、onents composed of routines for performingI/O and device control drivers are modules which are loadable at runtimeWindows has a formally defined driver model, Linux does not.PnP and power management support integrated in the Windows architecture, not so in LinuxConclusion (continued)A comparison of

17、the Windows and Linux IEEE 1394 stacks has shown thatTheir IEEE 1394 driver stacks are broken up into similar layers host controller, bus and client driver layersEach stack provides the standard IEEE 1394 operations (both asynchronous and isochronous)The Linux IEEE 1394 stack is open source while th

18、e Windows stack is proprietaryEasier to create IEEE 1394 drivers for Linux than Windows since all source code is availableFuture workIEEE 1394.1 bridge awarenessIEEE 1394.1 allows extending the no. of nodes to 64K instead of the current 63still in draft phaseThe Windows and Linux IEEE 1394 driver developers did not take into account IEEE1394.1 bridging in their designThi