From: "H . J . Lu" <hjl@lucon.org> Subject: Re: thread-ready ABIs Date: Fri, 18 Jan 2002 20:11:39 -0800 > I like the read-only k0 idea. We just need to make a system call to > tell kernel what value to put in k0 before returning to the user space. > It shouldn't be too hard to implement. I will try it next week. > > > H.J. Please don't use k1, we already use k1 to implement fast test-and-set method for MIPS1 machine. We plan to mereg the method into main glibc and kernel tree. You can use test-and-set without systemcall on MIPS1 machines using this method. You can find the paper described about it in http://lc.linux.or.jp/lc2001/papers/tas-ps2-paper.pdf (sorry in japanese only) The abstract of the paper attached below; The Implementation of user level test-and-set on PS2 Linux In the multi-thread environment like Linux, a fast user-level mutual exclusion mechanism is strongly required. But MIPS chips designed for embedded and single processor, like the Emotion Engine, have no atomic test-and-set instruction. We implemented the fast user-level mutual exclusion without invoking system-call and its costs, on the PS2 Linux. This method utilizes the memory protection facility of Operating System, to detect preemption and nullify the operation. In this paper, we present the method and its evaluation. --- Hiroyuki Machida Sony Corp.
