l4-hackers March 2006

l4-hackers@os.inf.tu-dresden.de

19 participants
14 discussions

Strange L4Linux behavior
by Jugwan Eom 14 Apr '06

14 Apr '06

Hi, L4Linux fails to run correctly with the SCSI and network device under heavy load. My system has a Adaptec AIC7902 SCSI adapter (one SCSI hard disk is connected) and a E1000 network adapter. When the two devices is used at the same time under heavy load (some benchmarks to SCSI disk and transferring files using ftp), SCSI adapter driver prints error message and dumps device's status. and then system is not work. Actually, this error doesn't happen immediately after using the two devices. It works during some seconds (about 10~20secs). I could not capture all the message by SCSI adapter driver printed on console because it is very fast and vast. Anyway, the message means "PCI interrupt error". In L4Linux, the two devices share same IRQ number. IMHO, this is one of the source of this behavior. To use SCSI in L4Linux, I use dm_phys with '--isa=0x00800000' option. Two different IRQ handling methods (one thread per IRQ and multiple IRQs) got the same result. Is there anyone can help me? Regards, -- Jugwan Eom

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Lovelace Web-Site
by Frederic BOYER 30 Mar '06

30 Mar '06

By the way, Lovelace has now a little web-site (I've just began to do it) and there is a mailing list. Please visit The Lovelace web-site. http://lovelace.rochebrune.org Regards, Frédéric. "This message, including any attachments may contain confidential and privileged material; it is intended only for the person to whom it is addressed. Its contents do not constitute a commitment by Credit Agricole Cheuvreux except where provided for in a written agreement. Credit Agricole Cheuvreux assumes no liability or responsibility for the consequences arising out of a delay and/or loss in transit of this message, or for corruption or other error(s) arising in its transmission and for any misuse or fraudulent use which may be made thereof. If you are not the intended recipient, please contact us and abstain from any disclosure, use or dissemination. To the extent that this message contains research information and/or recommendations, these are provided on the same basis as Credit Agricole Cheuvreux's published research and the recipient must have regard to all disclosures and disclaimers contained therein."

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L4Linux without libloader?
by Daniel Vandersee 23 Mar '06

23 Mar '06

Hi there, is it possible to compile L4Linux without the need of libloader.s.so (e.g. by using other libs) to have it statically linked? Thanks, Daniel

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Reloading L4Linux problem
by Jugwan Eom 17 Mar '06

17 Mar '06

Hi. I encountered problems reloading L4Linux. After shutdown loaded L4Linux, I tried reloading the L4Linux (same configuration) using 'l' command in l4con but it didn't work(network device probe failed, lost ide disk interrupt). During booting L4linux showed "irq_thread: RMGR denied IRQ 14: code 0x1". Because I use l4con, I can see the system memory on bottom right. After shutdown loaded L4Linux, it still shows the same value before. Using 'a' command in l4con memory region used by previous L4Linux seem to be still allocated. IMHO, this is the source to fail to reloading L4Linux. Because memory region by used L4Linux includes the DMA region, reloading L4Linux cannot control the system device. Is this a bug in L4Linux or other L4Env server? Also, see the attached log. Best regards, -- Jugwan Eom

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What is trampoline.S for?
by BVK Groups 17 Mar '06

17 Mar '06

Hi, Whenever i try to start executing first thread in a new address space, its pager is receiving pagefault (at 0x0000002b), eventhough none of the mapped code touches that place. Why is it? I found out that CHACMOS is mapping trampoline.S at that address. I What is this trampoline.S is for? I tried to understand trampoline.S code, but i couldn't. I didnt find any FAQ entry regarding this. Can anyone please help me here? NOTE: I am using pistachio-0.4 Thanks, -bvk

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Announce: OS Group of TU Dresden (TUD:OS) releases Live-Demo CD
by Norman Feske 13 Mar '06

13 Mar '06

The OS Group of Technische Universität Dresden (TUD:OS) has released a live demo CD of our operating system project. Some highlights of the Demo CD include a new approach for securing graphical user interfaces called Nitpicker, multiple L4Linux kernels running at the same time on top of a L4/Fiasco, a survey on our reuse of device drivers on the TUD:OS platform, native Qt-applications, the DOpE windowing system and a prototype of a secure E-commerce application based on TUD:OS. More information, an ISO image, and screenshots are available at the demo CD website: http://demo.tudos.org Norman Feske TU Dresden Operating Systems Group

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some weird performance result
by Sungkwan Heo 11 Mar '06

11 Mar '06

Hi all, I measured network I/O performance of native Linux-2.4 and Fiasco-1.2+L4Linux-2.4 using the netperf benchmark. The TCP streaming test results are following: Recv Socket Size bytes: Linux = 87380, L4Linux = 87380 Send Socket Size bytes: Linux = 16384, L4Linux = 16384 Send Message Size bytes: Linux = 16384, L4Linux=16384 Elapsed Time secs: Linux = 10.002, L4Linux = 10.002 Throughput MBytes/s: Linux = 11.22, L4Linux = 11.206 Utilization Send local % S: Linux = 11.359, L4Linux = 4.35 ... The last 2 lines indicates the network I/O throughput and CPU utilization for the network I/O. One weird thing is the L4Linux CPU utilization. It spent much less CPU cycles than the native Linux did. In my humble opinion, it is normal case because the L4 Fiasco schedules the L4Linux application (netperf) as a L4 process and L4Linux kernel doesn't have correct CPU usage information of the application. Is it correct?

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config for 2 L4Linux instances
by Sungkwan Heo 11 Mar '06

11 Mar '06

Hi all, Is there anyone who succeeded in running multiple L4Linux (2.4 or 2.6) instances on native fiasco, not fiasco-ux? If so, could I share the configuration and howto? Especially, I want to boot L4Linux-2.4 mounting root disk partition where RedHat 9.0 is already installed. I expect that another L4Linux-2.4 image can be loaded MODFS or TFTP. However I can't figure out how I can setup my L4 box to load any application that I want from where I want. Another issue is the second L4Linux need another root partition or not. Is it possible to the first L4Linux use hard disk partition and the second one use ramdrive? And as far as I know, the main purpose of fiasco-ux is just emulation and not real solution that has similiar architecture to WMware. right?

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Update on NICTA's secure embedded L4 project
by Kevin Elphinstone 10 Mar '06

10 Mar '06

Hi All, I'm please to announce the release of more information on the secure embedded L4 (seL4) project, including a reference manual of the experimental kernel API. You can get more info on the project's web page at http://www.ertos.nicta.com.au/research/sel4/ cheers - Kevin Dr. Kevin Elphinstone Senior Researcher and seL4 Project Leader National ICT Australia

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L4.Sec Implementation
by Anton Soppelsa 08 Mar '06

08 Mar '06

Hi, My name is Anton Soppelsa and I'm doing a PhD course at the "Istituto Gas Ionizzati" (Ionized Gas Institute) in Padova (Italy). I am a control system engineer and at the moment I'm involved in some work with a Motorola mv5500 Single Board Computer installed in a VME rack. As I am a free software supporter and I don't like too much our working developing platform as is based on the proprietary VxWorks operative system. For this reason I am interested in GPL-ed real time operative systems. I read the specification of the L4.Sec system, but unfortunately I am not able to fully understand the concept of capability space. Probably this happens because I am one of those that need to see how things are made to catch the concept of what they really are. Even if I don't think, at this moment, that L4.Sec is exactly what I need (because speed is my real priority), I'm anyway curious about how it works. So if your new project is at a point where you actually have some structures, or classes implementing the capability space, will your team be so kind to send me that piece of code? I will read it with interest in my spare time. Many thanks, Anton

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l4-hackers March 2006