l4-hackers

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2827 discussions

Ein paar Fragen/Anmerkungen zur neuen Directory Struktur
by Jean Wolter 04 Jun '99

04 Jun '99

Hallo, nachdem nun etwas Zeit für die liegen gebliebenen Arbeiten ist, habe ich versucht, das Repository zu übersetzen. Das ging natürlich nicht. Zwei Gründe: 1. Die privaten Includedirs sind nicht gesetzt (mit einem "PRIVATE_INCDIR='../include' make" kommt man ein Stück weiter). Sollen die privaten includes lokal gesetzt werden, dann müssen alle Makefiles angepaßt werden oder setzen wir das global? 2. Es gibt Unstimmigkeiten über die Lokation der L4 Headerfiles (ehemals libl4sys). Micha vermutet sie unter l4/sys/, sie liegen aber unter l4/. Was ist nun richtig und wer passt es an? Jean -- I get up each morning, gather my wits. Pick up the paper, read the obits. if I'm not there I know I'm not dead. So I eat a good breakfast and go back to bed. Peete Seeger

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Re:
by Michael Hohmuth 31 May '99

31 May '99

"benben xiao" <xiaoxiaoben(a)hotmail.com> writes: > When I see fiasco kernel, I have a simple question: > I don't know > #if 0 > ... > ... > #endif > what do '0' mean there? This is a way to comment out unused code: Everything between "#if 0" and "#endif" is stripped by the preprocessor, and is ignored by the compiler. For more information about the C/C++ preprocessor, please refer to the GNU CPP manual. On most systems, you can browse it with "info cpp". The answer to your particular question is in "info cpp conditional deletion". Michael -- hohmuth(a)innocent.com, hohmuth(a)sax.de http://www.sax.de/~hohmuth/

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Re: Default attributes of tasks/lthreads
by Michael Hohmuth 31 May '99

31 May '99

Robert Kaiser <rob(a)sysgo.de> writes: > The question came up while writing a test suite for a microkernel > we are currently developing. It's API is not identical, but quite > similar to L4's (we would like to run L4Linux on it in the future). If your kernel's API is similar enough: Is there a chance of releasing your test suite as open source? We probably could adapt it to our implementations, and having a test suite for Fiasco and L4/x86 would be very useful. > I can certainly handle this behavior, but I was just wondering > what would be a "clean" design. From what I just learned, there > is in fact a difference between a thread being created and a thread > being re-started into a new context: In the first case, the thread's > scheduling parameters are inherited from the caller, in the latter > case, they retain whatever values they had before. So the caller > of lthread_ex_regs has to be aware of wether the thread already > exists or not. Yes, that's true. What you proposed earlier in this thread (make it possible to set scheduling parameters for not-yet-existing local threads) seems to be somewhat cleaner, but I think the current behavior isn't very difficult to handle; tasks have to keep track of thread states anyway because they manage the allocation of local thread ids themselves. Michael -- hohmuth(a)innocent.com, hohmuth(a)inf.tu-dresden.de http://home.pages.de/~hohmuth/

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Re: Default attributes of tasks/lthreads
by Michael Hohmuth 31 May '99

31 May '99

Robert Kaiser <rob(a)sysgo.de> writes: > I have a question regarding the default scheduling parameters > of newly created tasks and lthreads under L4: > > When I create a new task with the task_new syscall, according > to the L4 manual, that task's lthread 0 starts running immediately. > > But what are it's scheduling parameters (timeslice duration, > priority) in this case ? > > Similarly, when I create a new lthread with lthread_ex_regs, > how are it's scheduling parameters determined ? The parameters are inherited from the creating thread. There usually is a way to change the parameters before the new thread starts running: Use the thread_schedule system call before serving the thread's first page fault. > Also, is it possible to set these parameters for an lthread > that does not yet exist (The manual doesn't explicitly state > this, but the fact that -conceptually- all lthreads of a task > always exist would suggest that this is indeed possible) ? Good question. I think this is not really defined in the manual. The current implementations don't support what you suggest; instead, the scheduling parameters are inherited from the creating thread once the new thread is ``really'' created. Do you have an application where this behavior is a problem? Michael -- hohmuth(a)innocent.com, hohmuth(a)sax.de http://www.sax.de/~hohmuth/

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(no subject)
by benben xiao 31 May '99

31 May '99

Hi Hackers: When I see fiasco kernel, I have a simple question: I don't know #if 0 ... ... #endif what do '0' mean there? Please pardon my poor english! Thank you! ______________________________________________________ Get Your Private, Free Email at http://www.hotmail.com

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Default attributes of tasks/lthreads
by Robert Kaiser 27 May '99

27 May '99

Hi Hackers, I have a question regarding the default scheduling parameters of newly created tasks and lthreads under L4: When I create a new task with the task_new syscall, according to the L4 manual, that task's lthread 0 starts running immediately. But what are it's scheduling parameters (timeslice duration, priority) in this case ? Similarly, when I create a new lthread with lthread_ex_regs, how are it's scheduling parameters determined ? Also, is it possible to set these parameters for an lthread that does not yet exist (The manual doesn't explicitly state this, but the fact that -conceptually- all lthreads of a task always exist would suggest that this is indeed possible) ? Thanks for any response Rob ---------------------------------------------------------------- Robert Kaiser email: rkaiser(a)sysgo.de SYSGO RTS GmbH Carl-Zeiss-Str. 41 phone: (49) 6131 9138-80 D-55129 Mainz / Germany fax: (49) 6131 9138-10

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Re: GMD paper
by Michael Hohmuth 25 May '99

25 May '99

I wrote a few minutes ago: > This paper is now available (along with many other interesting papers > from Jochen) from <URL:http://i30www.ira.uka.de/images/b_publications_on.gif>. ^^^^ Oops, although you probably like GIFs, this one isn't of particular utility. Here's the correct URL: <URL:http://i30www.ira.uka.de/publications/index.html>. Michael -- hohmuth(a)innocent.com, hohmuth(a)inf.tu-dresden.de http://home.pages.de/~hohmuth/

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Re: GMD paper
by Michael Hohmuth 25 May '99

25 May '99

"Adam 'WeirdArms' Wiggins" <awiggins(a)cse.unsw.edu.au writes: > Anyone know where I can get a copy of: > > Jochen Liedtke: > Improved Address Space Switching on Pentium Processors by > Transparently Multiplexing User Address Spaces > (GMD technical report) This paper is now available (along with many other interesting papers from Jochen) from <URL:http://i30www.ira.uka.de/images/b_publications_on.gif>. The URL for the paper you're looking for is <URL:http://i30www.ira.uka.de/publications/pubcat/As-pent.ps>. Michael -- hohmuth(a)innocent.com, hohmuth(a)sax.de http://www.sax.de/~hohmuth/

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Re: Please help me!
by Michael Hohmuth 25 May '99

25 May '99

"benben xiao" <xiaoxiaoben(a)hotmail.com> writes: > Hi; > When I see the file "init.h" in "l4/server/sigma0/src/",I meet a problem. > Although I have know: > #define L4_NORETURN __attribute__((noreturn)) > but I don't understand the function definition: > void init(struct multiboot_info *mbi, unsigned int flag, > l4_kernel_info_t *info) L4_NORETURN; > there why we can use "L4_NORETURN" and what is the effect of > "L4_NORETURN". __attribute__((noreturn)) is an extension supported by the GNU C compiler. It is intended to be used with functions that are not supposed to return. When a function declared with this attribute looks like it returns anyway, the compiler issues a warning. Please consult the Gcc documentation for more details (on most system, you can run "info gcc 'c extensions' 'function attr'"). Michael -- hohmuth(a)innocent.com, hohmuth(a)inf.tu-dresden.de http://home.pages.de/~hohmuth/

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Re: basis of L4-Linux
by Michael Hohmuth 25 May '99

25 May '99

suzukis(a)file.phys.tohoku.ac.jp writes: > uname returned Linux 2.0.21(or 20?) - I remember, L4-Linux > seems to be based old kernel source. But the L4-Linux source > also seems to include something taken from later kernel > source (ex. Configure.help). L4-Linux will be rewritten > from the later Linux kernel (ex. 2.0.36, or 2.2.x)? > Or, will be a branch from the old kernel? We have been working internally on a port of Linux 2.2 to L4, and I'm positive that we can release it ``soon.'' > If asking about L4-Linux is off-topic, please let me know > who/where I could ask about L4-Linux. No, that's fine, you're on-topic. Michael -- hohmuth(a)innocent.com, hohmuth(a)inf.tu-dresden.de http://home.pages.de/~hohmuth/

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