- Kernel Sceduler Behavior (Tempolary) ¡ÊMr. Matsubara, Igel¡Ë * Story in the past presentations Have been investigating behavior of RT tasks snd non-RT tasks. The goal is to implement device drivers in user land. * Today's presentation Actually implemented a device driver in user land. Will report it. * Current status in embedded development More development of new device drivers Development in user land would be easier. * For embedded, user space device driver may be practical - Benefit Use of tools/libraries Ease of development and debugging Less system hang ups - Then, what features necessary for device drivers? Access to I/O memory Interrupt receipt and handling Allocation of and access to physical memory * In user process, general threads and device processing threads can share memory area and cooperate * Investigation of performance of user space device drivers It turned out that user space device drivers are sometimes faster, depending on conditions. No problem for handling synchronous interrupt. Otherwise, it might be difficult. * Q&A - Throughput was reported in the presenation. How about latency? To be measured. - Try signal? Although the report was blocking I/O, how would it be with non-blocking I/O? For example, waking up with signals? - Comment Want to know up to how much K will it be transferrable with this serial transfer without dropping data.