- l4-hackers - example.com Site

About consuming time slice on l4linux
by Jungwoo Yang 17 May '10

17 May '10

I know that l4linux cpu always is allocated on 4th thread on linux server. Also, I want to assign specific timeslice into the linux CPU thread to operate its linux kernel and its user task. To do this, I wanted to be expected in one of linux can use CPU more than another linux. However, even though I assigned timeslice more (it can be done by adding schedule context), 2 linux servers is seemed to be using almost same the amount of CPU. I think that this is because of idle thread. If idle thread is executed, other linux can preempt the linux. Am I right? also, I'm wondering whether user task consumes their own timeslice or donated timeslice from CPU thread. Thank you

2 1

Re: The system call about Periodic task
by Jungwoo Yang 13 May '10

13 May '10

I've found that this code is not wrong. The problem was from IPC control in thread-ipc.c in sys-ipc() function, the kernel check whether the ipc is next_period() or not, but the check function is wrong i think because the function returns always "FALSE". That means that there is no next_period() ipc. so I've changed the code in shared/entry_frame-ia32-ux.cpp line 110 return false; --> return (_ecx == 0x04000400 && _esi == 0); I'm not sure that this code does not affect to the other ipc. However it is executing quite well. Jungwoo Yang.

1 0

irq handling in DDE Linux26
by Da Zheng 12 May '10

12 May '10

Hello, In DDE Linux26, the interrupt is ignored when an interrupt line is disabled, i.e., the handle_irq field of ddekit_irq_ctrl is 0. In ne2k-pci, an example in DDE Linux26, when a packet is transmitted by the driver, disable_irq_nosync_lockdep_irqsave() is called to disable irq. Then it triggers a send and calls enable_irq_lockdep_irqrestore(). Now the problem is that after a packet is transmitted, the transmission-done interrupt can be delivered before enable_irq_lockdep_irqrestore is called, so the interrupt is ignored and the driver thinks the packet cannot be transmitted. This situation happens when I run ne2k-pci in the Hurd porting of DDE Linux26. disable_irq_nosync_lockdep_irqsave is exactly the same as disable_irq_nosync when there isn't CONFIG_LOCKDEP. It seems to me that ne2k-pci shouldn't call it in the first place when transmitting packets, but Linux drivers should be correct. Then what goes wrong? Should the interrupt handler delays interrupts instead of ignoring them silently when the interrupt line is disabled? Best regards, Zheng Da

3 7

Problem in porting an application
by Karthik Vadambacheri Manian 10 May '10

10 May '10

Hi Adam, My application uses Time Warped simulation library which uses standard c++ library. The time warped library uses a class called multimap which has a default constructor in std c++ library while in uclibc++ there is no default constructor. Hence to conform to uclibc++ I need to pass few arguments to use the current constructor in uclibc++ but this screws up a bit. I can modify multimap in uclibc++ with a default constructor but I am not sure whether default constructor is omitted intentionally and has some side effects. Also I need to do this change to all classes it is inheriting. Thats why I thought is it possible to use std c++ library instead of uclibc++. Can I know the version of std c++ library that is ported to uclibc++? Thanks a lot for your comments. Regards, Karthik

2 1

Re: Problem in porting an application
by John van V. 09 May '10

09 May '10

Just so you know, I was a big person in information when it was centered in my home city of NY. Just as NYC's tech industry collapsed (mostly, I believe because of the bombing of the WTC--which itself was a headquarters of free software), I was completing the design criterion of the Thinman model, which is an extension of Perl's CPAN to a VM that is open to the Internet for both data and code. It is anti-app in that each object, presumably a dataset, is, as it is evoked, its own app. Your friends list, as a small example, becomes a phone book in a flexible browser, when it is evoked in the context of a phone call through a model or other connection. I personally know David Korn, which is significant to me, since I believe that his KSH, with its related commands and related shells such as BASH, has provided the best work, and play, environment we have. It has a little awkwardness (which is forgivable given it was a proof of concept at its inception in the 1970s), and no OO version Shell has been attempted. And needless to say, it lacked a visual desktop! Other than those few issues, I cannot help but believe his traditional open shell still provides a model of the type of interactive framework that we need to bring to L4 as the default interface. I have since taken social science paths, and perhaps because of this, I very much want to help work from the top down (as you are with your ground-breaking port) to the lower levels, where everybody else is, so that L4 growth can be what free software is really all about--our system! John van V. On Sun, May 9, 2010 at 1:02 PM, Karthik Vadambacheri Manian <karthikvm.uc(a)gmail.com> wrote: > Thanks for the comments John. Its very encouraging!! > > Regards, > Karthik > > On Sat, May 8, 2010 at 3:41 PM, John van V. <john.van.v(a)gmail.com> wrote: >> >> Great work, seriously! >> >> On Fri, May 7, 2010 at 12:17 PM, Karthik Vadambacheri Manian >> <karthikvm.uc(a)gmail.com> wrote: >> > Hi All, >> > >> > Currently I am trying to port a pingpong c++ application which uses time >> > warped libraries. The time warped libraries use standard c++ library >> > inturn. >> > I tried to compile the pingpong application by modifying the makefiles >> > to >> > include the time warped headers. But I get lot of errors while compiling >> > because during compilation the uclibc++ header files are used instead of >> > standard c++ headers and they differ. Hence I tried to port the warped >> > library functions for uclibc++ but it seems it needs a huge >> > modification. Do >> > modifying makefiles to use standard c++ header files instead of uclibc++ >> > will break other systems? Please let me know your comments. >> > >> > Thanks, >> > Karthik.V.M. >> > _______________________________________________ >> > l4-hackers mailing list

1 0

Problem in porting an application
by Karthik Vadambacheri Manian 08 May '10

08 May '10

Hi All, Currently I am trying to port a pingpong c++ application which uses time warped libraries. The time warped libraries use standard c++ library inturn. I tried to compile the pingpong application by modifying the makefiles to include the time warped headers. But I get lot of errors while compiling because during compilation the uclibc++ header files are used instead of standard c++ headers and they differ. Hence I tried to port the warped library functions for uclibc++ but it seems it needs a huge modification. Do modifying makefiles to use standard c++ header files instead of uclibc++ will break other systems? Please let me know your comments. Thanks, Karthik.V.M.

2 1

Re: Regd: L4 Reference and User manual
by kolabor＠freenet.de 28 Apr '10

28 Apr '10

Hi, after looking at the slides you pointed to (at http://www.inf.tu-dresden.de/index.php?node_id=1314&ln=en) the Fiasco for download isn't the one discussed in the slides, right ? So it seems that stuff discussed in your lectures are newer than that what is available for download, esp. the capability part. Also in your recent publications you are speaking about Fiasco.OC and L4Re and not about Fiasco 1.2 and/or L4Env. So what does this all mean ? They are related or is that completly new stuff and just rebranded to known/established names. Some enlightenment would be nice. (Intention of my mail: Try to figure out whether it is worth to start porting stuff to old? outdated? Fiasco 1.2 or to wait [how long?] for the newer stuff you discussing in your slides. Don't want to write or to port stuff twice, probably also interesting for the request of the MPI stuff some days ago.) Tim. > -----Ursprüngliche Nachricht----- > Von: Adam Lackorzynski > Gesendet: Mi. 28.04.10 (00:03) > An: l4-hackers(a)os.inf.tu-dresden.de > Betreff: Re: Regd: L4 Reference and User manual > > > On Mon Apr 26, 2010 at 14:32:21 -0400, Karthik Vadambacheri Manian > wrote: > > I am working on Fiasco compiled for AMD64 architecture. Can some > one point > > which L4 reference manual to read? > > Also the user manual by Alan Au and Gernot Heiser seems to be old. > Is it > > still valid? please let me know. > > For the version of Fiasco you are looking at it is still ok. Also I > think you can learn a lot about the concepts etc. > > > > Adam > -- > Adam adam(a)os.inf.tu-dresden.de > Lackorzynski http://os.inf.tu-dresden.de/~adam/ > > _______________________________________________ > l4-hackers mailing list > l4-hackers(a)os.inf.tu-dresden.de > http://os.inf.tu-dresden.de/mailman/listinfo/l4-hackers > > > -----Ursprüngliche Nachricht Ende----- freenetMail mobil – Alle E-Mails auf Ihrem Handy versenden und empfangen. Jetzt kinderleicht und kostenlos einrichten. http://tls.freenet.de/tipp/handymail/index.html

2 1

The system call about Periodic task
by Jungwoo Yang 28 Apr '10

28 Apr '10

I tried to use time periodic task designed by Udo. However, the process using the system call does not enter into periodic mode. So I tried to analyze kernel source code. During examining kernel source code, I found the wired point. line 584 in syscalls.cpp regs->old_param (dst->begin_periodic (regs->time(), 0)); I think that the parameter should be "Periodic" instead of 0. Because the point is for entering periodic mode and 0 means that conventional mode, I think 0 should be changed into "Periodic". After modification of this, A task using the system call enters periodic mode ( I check this by using JDB debugger ). I cannot ensure that this is correct code, but It seems to be working. So, if anyone who want to use periodic task and think that it is not working, just try to modify this code. Thank you for Adam Lackorzynski and Cheng Cuanghui Thank you. Regards, Jungwoo Yang.

1 0

Regd: L4 Reference and User manual
by Karthik Vadambacheri Manian 27 Apr '10

27 Apr '10

Hi All, I am working on Fiasco compiled for AMD64 architecture. Can some one point which L4 reference manual to read? Also the user manual by Alan Au and Gernot Heiser seems to be old. Is it still valid? please let me know. Thanks for your time, karthik <l4-hackers(a)os.inf.tu-dresden.de>

2 1

L4 and ARM Cortex-A8 (OMAP3)
by Thomas DuBuisson 26 Apr '10

26 Apr '10

All, I'm wanting to experiment with L4 on a OMAP3 (beagleboard based) system but am having difficulting finding a suitable L4 microkernel. Does anyone on this list have comments/suggestions wrt which kernel to use, building, u-boot configuration, etc? Cheers, Thomas

2 2