On Sat, 24 Feb 2007, Kyle Moffett wrote: > On Feb 24, 2007, at 16:10:33, Davide Libenzi wrote: > > On Sat, 24 Feb 2007, Ingo Molnar wrote: > > > the on/off calls are shaped in a way that makes them ultimately > > > vsyscall-able - the kernel only needs to know about the fact that we are > > > in a threadlet (so that the scheduler can do its special > > > push-head-to-another-context thing) - and this can be signalled via a > > > small user-space-side info structure as well, put into the TLS. > > > > IMO it's not a matter of speed. We'll have those two new syscalls, that I > > don't see other practical use for. IMO the best thing would be to hide all > > inside the sys_threadlet_exec (or whatever name). > > No, it absolutely is a matter of speed. The reason to have those two > implemented that way is so that they can be implemented as vsyscalls > completely in userspace. This means that on most modern platforms you can > implement the "make a threadlet when I block" semantic without even touching > kernel-mode. The way it's set up all you'd have to do is save some > parameters, set up a new callstack, and poke a "1" into a memory address in > the TLS. To stop, you effectively just poke a "0" into the spot in the TLS > and either return or terminate the thread.
Right. I don't why but I got the implression Ingo's threadlet_exec example was just sketch code to be moved in a syscall. That's why I was talking about a sys_threadlet_exec. But yeah, it makes a lot of sense to turn threadlet_exec in a glibc thing, and play everything in userspace at that point. - Davide - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
