l4-hackers August 2013

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

17 participants
20 discussions

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NOVA, NUL, snapshotting
by Sartakov A. Vasily 13 Jan '14

13 Jan '14

Hello. Does the NOVA/NUL support snapshotting of VMes? -- Sartakov A. Vasily

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Fosdem'14
by Sartakov A. Vasily 09 Sep '13

09 Sep '13

Hello, my dear friends. I am sorry if you receive multiple copies of this message (but I know, most of you will receive copies), but mailing list from uKernel dev room at FOSDEM'13 was destroyed (https://lists.fosdem.org/listinfo). Time rolls on, a FOSDEM'14 is not too far and now it is good time to submit a "uKernel and component based os" dev room. Who would like to organize dev room in this year? I would be proud to make this, but I heard someone from TUD would like to organize Dev room in this year. -- Sartakov A. Vasily sartakov(a)ksyslabs.org

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Cross-CPU TLB flush problem with Fiasco.OC (r56, r58; exynos5)
by Christian Prochaska 01 Sep '13

01 Sep '13

Hello, I had a situation where CPU 1 accessed the wrong (same as before) physical memory location after it was idle while CPU 0 unmapped the memory page and mapped a different page at the same virtual address afterwards. When a CPU is idle, its TLB gets marked as 'inactive' in the kernel and the CPU doesn't receive cross-CPU TLB flush requests during this time. It seems there is a TLB flush missing somewhere after CPU 1 leaves the idle thread, to compensate for any missed flush requests during the idle time. When I added a 'Mem_unit::tlb_flush()' call after 'enable_tlb(cpu)' in 'Kernel_thread::idle_op()' as a test, this problem did not occur anymore. Christian

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Top runscript
by Daniel Müller 28 Aug '13

28 Aug '13

Hello, I've seen the l4/pkg/top package and find it to be quite interesting. Can someone point me to a lua-runscript to start a program to be monitored by it? What caps do I have to redirect? Thanks, Daniel

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Data transfer mechanisms
by Lluís Vilanova 20 Aug '13

20 Aug '13

Hi, I'd like to compare the performance of two different synchronous data transfer mechanisms: * Copies * Page maps / unmaps For the second one, it looks like I can use the streammap example (pkg/examples/libs/l4re/streammap), although I'm lacking a mechanism to unmap the page before returning control to the client. It would also be nice to be able to pass the server a read-only region. For the first one, I've only found the use of multiple send/recv operations through the limited amount of data available on the message registers. There is a "Gen_string" class in the "ipc_stream" header, which looks like it could support offline string transfers, but it's disabled at compile time and I could not find the actual code in fiasco that handles these transfers. Thanks, Lluis -- "And it's much the same thing with knowledge, for whenever you learn something new, the whole world becomes that much richer." -- The Princess of Pure Reason, as told by Norton Juster in The Phantom Tollbooth

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Files that Tune Kernel
by Bryan Amato 18 Aug '13

18 Aug '13

Hello everyone, I was wondering what files are the ones that increase the performance of the kernel, besides kernel.hz. Reading in a post by L4, they say that the kernel was not tuned like the Mach Linux port. But I wanted to edit those files to increase performance and to also learn more about what that particular file does. I tried doing this once, but my whole kernel got corrupted from my lack of knowing what is able to be edited and things that had to be there so it could be booted properly. Thanks!

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Desktop Environment
by Bryan Amato 17 Aug '13

17 Aug '13

Hello everyone, I have been using Linux for sometime and only recently tried a special version of BSD, named Dragonfly BSD. What I liked about Dragonfly is that the kernel is not a monolithic kernel. However BSD is not really for me, I prefer the comfort of Linux, so I began searching around the web for a non-monolithic version of the Linux kernel and I came across L4Linux. Looking at the screenshots, I don't see any modern DE's. Does L4L support those desktops like KDE, Gnome and E17? Thanks for all the work you guys are putting into this kernel!

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How to write device driver
by Raja Sekhar 16 Aug '13

16 Aug '13

Hello to all, I want to write a simple character device driver.Can you please give me the procedure for writing device drivers for L4fiasco. * Thanks,* Raja Sekhar

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l4linux with ide-harddisk
by Rudolf Weber 16 Aug '13

16 Aug '13

Hello, I prepared a 32 bit ubuntu system on a virtualbox and replaced the linux - Kernel through the l4re-snapshot-2013060718 - L4Linux-mag-x86 Konfiguration. First I made a disk and add it to the vm and I could mount it ! I wonder ( see later). Now I configured the Ubuntu-Linux-Root-Disk as /dev/hda and: ... piix 0000:00:03.0: IDE controller (0x8086:0x7111 rev 0x01) pci 0000:00:03.0: No interrupt pin configured for device 0000:00:03.0 piix 0000:00:03.0: not 100% native mode: will probe irqs later ide0: BM-DMA at 0xd000-0xd007 ide1: BM-DMA at 0xd008-0xd00f hdc: VBOX CD-ROM, ATAPI CD/DVD-ROM drive hdc: UDMA/33 mode selected ide0 at 0x1f0-0x1f7,0x3f6 on irq 14 ESC[37mio | ERROR: binding irq 15, result is -1 (Operation not permitted) ESC[0m ESC[33ml4linux | Bind irq to icu failed with -1ESC[0m l4x-irq: Did not get IRQ 15 from IO service ==> I think, the interupt is not delegated from the IO-Server to l4linux My understanding is, that the io-Server manage all interrupts,ioports. But why I could mount a disk ? I dont see a device in x86-legacy.dev, so I add IDE0 and IDE1 (see attachment), and add a systembus disks => new System_bus() { IDE0 => wrap(hw-root.match("ide0")); IDE1 => wrap(hw-root.match("ide1")); } in l4lx-x86.io (see attachment) in the start-config l4lx-gfx.cfg the disks are granted to l4linux (see attachment) As result, the output is piix 0000:00:03.0: IDE controller (0x8086:0x7111 rev 0x01) pci 0000:00:03.0: No interrupt pin configured for device 0000:00:03.0 piix 0000:00:03.0: not 100% native mode: will probe irqs later ide0: BM-DMA at 0xd000-0xd007 ide1: BM-DMA at 0xd008-0xd00f hda: VBOX HARDDISK, ATA DISK drive hda: UDMA/33 mode selected hdc: VBOX CD-ROM, ATAPI CD/DVD-ROM drive Switching to clocksource tsc hdc: UDMA/33 mode selected ide0 at 0x1f0-0x1f7,0x3f6 on irq 14 ESC[33ml4linux | Bind irq to icu failed with -1ESC[0m l4x-irq: Did not get IRQ 15 from IO service ------------[ cut here ]------------ WARNING: at /home/rw/l4exp/l4re-snapshot-2013060718/src/l4linux/arch/l4/l4lxlib/ l4env/irq_vcpu.c:106 l4lx_irq_dev_startup+0x17a/0x180() Modules linked in: Pid: 1, comm: swapper Not tainted 3.9.0-l4 #1 Call Trace: -> the ERROR "ERROR: binding irq 15, result is -1 (Operation not permitted)" don't appear, but the result is the same. The current output of the serialine is in l4ubuntu.1 The l4-linux I configured with PCI/VPCI see attatchment x86_rw_config like in my last E-mails. Summary: * How to grant the ide-Controllers to l4linux ? * Why l4Linux can't get the interrupt - what is wrong with my configuration ? HW-Question: How are the IDE-Controllers and the PCI related ? Thank you very much Rudolf Weber

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issue in getting vhw_devices....................
by Raja Sekhar 13 Aug '13

13 Aug '13

Hello to all, I've downloaded l4re-core-2013041501.tar.bz2 and extracted and compiled fiasco kernel with following configuration Architecture-> IA-32 processor family, Platform -> PC Platform, CPU -> Intel Pentium Pro After that i compiled L4re env....and I just ran one example ux-vhw(which is the code for display Virtual hardware device). In that I'm getting value *'0'* for the fileld *vhw_offset *from the kernel info structure *struct l4_re_kernel_info_t.* Why It is giving zero and what does it mean....* Thanks*, Raja Sekhar

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l4-hackers August 2013