Date: Sun, 18 Feb 2001 09:52:37 -0500 From: Seth Leigh <seth@pengar.com> To: Julian Elischer <julian@elischer.org> Cc: freebsd-smp@FreeBSD.ORG Subject: Re: Well I read the stuff, and I get it now. Message-ID: <5.0.2.1.0.20010218094431.00aaf0a8@hobbiton.shire.net> In-Reply-To: <3A8F8495.F7313ECD@elischer.org> References: <5.0.2.1.0.20010218021929.00aaef98@hobbiton.shire.net>
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At 12:15 AM 2/18/2001 -0800, Julian Elischer wrote: >Seth Leigh wrote: >Basically all returns from the kernel to the user process might go first >via the UTS (Userland Thread Scheduler). This includes page faults and >interrupts of some types. We have not completely decided how many >[snip] >The saved state of the thread (when a timer interrupt completes and >retunr is sent back to the UTS) is made to b ecompatible with all >stopped threads so that the interrupted thread looks like all the >other runnable threads, and the UTS can simply decide which to >restart. Ah, ok, I get it. So you are saying anytime the kernel takes over control on any given processor, the means of the kernel giving control back when it's done doing whatever it was doing would be to upcall back to the process in the context of that scheduler activation, allowing the threads library to be able to make the decision of whether to keep running that thread or not? That's pretty darn cool. Guys, I am very interested in this whole thing. It's making me want to pull out my old Cyrix 166 and install the lastest and greatest FreeBSD on it (it currently isn't running, and has 2.2.1 on it...) so I can try to get up to the code you guys are on and see if I can help out. I am brand spanking new to kernel stuff, so I am not making any promises. I have been paying attention to a lot of kernel talk, and reading some books and such, so I have a reasonable idea of how a lot of stuff works, at least at a high level. It will take me a while after I start delving into code to *really* get it, and be able to be helpful. Unfortunately I don't have a working FreeBSD machine right now. The hardware is there, just the software is way out of date and no longer properly configured. My 1 ghz AMD t-bird is running Win2K and Solaris 8 (well, the machine *was* running Solaris 8 until I upgraded to a new motherboard 3 weeks ago, I haven't booted back up into Solaris 8 yet since the upgrade since I don't know how well it's going to work since the device tree must look different now). Maybe I could get two more hard drives (there are already three in the machine) so I could install Linux and FreeBSD on it too. Yeah, that's the idea. Seth To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-smp" in the body of the message
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