June 2013 - kernelnewbies@kernelnewbies.org - Kernelnewbies Mailing Lists

Why is that the write speed of DDR SDRAM are faster than the DDR2
by devendra.aaru June 4, 2013

June 4, 2013

Hello, I have two different types of hardware, one with DDR SDRAM and another DDR2, i tested them with bw_mem tool for write bandwidths, seems that at higher writes of >512kbytes the DDR is faster than the DDR2(more than 40%). But when compared to reads, DDR is slower (more than 50%). I couldn't find any reference that explains why. AFAIK, the DDR2 works double the faster rate than the DDR. any ideas? Thanks,

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assembly of packets
by Varun Sharma June 4, 2013

June 4, 2013

Hi, If TSO(tcp segmentation offload ) is enabled then nic card handle segmentation then where is assembly of packets happens ? Is it tcp_rcv_established function ?

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Clarifications on PFN_UP(x) macro
by stl June 4, 2013

June 4, 2013

Hello, I need some clarifications concerning the macro #define PFN_UP(x) (((x) + PAGE_SIZE-1) >> PAGE_SHIFT) found in "pfn.h" I suppose that its aim is to give the page frame number of the page following the page holding the physical address x, contrary to PFN_DOWN(x) which give the page frame number of the page holding the address x. Assuming that the first page has the range 0x0000 to 0x0FFF, the second 0x1000 to 0x1FFF and so on, it seems that there is an issu with the starting address of each page, for example: x = 0x10000 (PFN number 10) 0x10000 + 0xFFF >> 12 = 10, but should be 11 no? I certainly misunderstood something. Could someone clarify this point please? Thanks.

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Getting started on Linux Kernel Development
by Daniel Hamacher June 3, 2013

June 3, 2013

Greetings. My name is Daniel and I am starting out in Linux Kernel development on a Debian Linux distribution. I followed the steps on kernelnewbies.org and I am booting now with 3.10.0-rc3+. So I build the compiler and I am also booting from it. I watched the video from Greg Kroah-Hartman on how to submit patches, I created a branch, so I am ready to go... How do I get started with the Kernel janitors to get my feet wet? I have intermediate knowledge of C and basic knowledge of Assembly. Is there anything in particular that I can get started on? Thanks. Cheers, Daniel

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tracing send and recv system call
by Varun Sharma June 3, 2013

June 3, 2013

Hi, I am tracing send and recv system call .From user space to kernel space switching send in kernel space not going into sys_send .It directly going into sys_sendto . I am using linux 2.6.32.60 for this operation.my printk statement is printed in sys_sendto but not in sys_send. Is it right way of calling.

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Ti am335x usb pll configuration
by Jelle Sels June 3, 2013

June 3, 2013

Hey, Is there a way to configure the pll settings of the usb (TI am335x) in a dtsi file (kernel 3.8)? For a design we are using a 24 mhz oscilator instead of a 25 mhz oscilator. Thanks

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Source based routing
by Adel Qodmani June 2, 2013

June 2, 2013

Hello everyone, I'm trying to force the kernel into using a source-based routing in my kernel module. What I mean by this is that I want packets with IP: X to go through the interface that has the IP: X. So far, I found out how to do that using IPTABLES, but I want to force this policy programmatically, is there any way to do so? Best regards, Adel

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Re: LTS and LTSI
by jeshkumar555＠gmail.com June 2, 2013

June 2, 2013

Thanks Abbas :) Sent from my HTC ----- Reply message ----- From: "Saqlain Abbas" <saqlain.abbas.7(a)gmail.com> Date: Sun, Jun 2, 2013 10:38 am Subject: LTS and LTSI To: "jeshkumar555(a)gmail.com" <jeshkumar555(a)gmail.com> Cc: "kernelnewbies" <kernelnewbies(a)kernelnewbies.org> http://ltsi.linuxfoundation.org/what-is-ltsi https://wiki.ubuntu.com/LTS Cheers, Saqlain. On Sun, Jun 2, 2013 at 9:34 AM, jeshkumar555(a)gmail.com < jeshkumar555(a)gmail.com> wrote: > Hello :), > > What is the difference between LTS and LTSI kernel ? > > Thanks, > > Regards, > Jeshwanth > Bangalore > Sent from my HTC > > > _______________________________________________ > Kernelnewbies mailing list > Kernelnewbies(a)kernelnewbies.org > http://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies > > -- Kind Regards, Saqlain Abbas.

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LTS and LTSI
by jeshkumar555＠gmail.com June 2, 2013

June 2, 2013

Hello :), What is the difference between LTS and LTSI kernel ? Thanks, Regards, Jeshwanth Bangalore Sent from my HTC

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Install kernel headers
by Parmenides June 1, 2013

June 1, 2013

Hi, I try to define a new system call in the kernel for experimental purpose. After hack the kernel code, I remade the kernel code. But the new system call number is declacred in kernel header 'asm/unistd.h'. For the sake of reference by applications, it is necessary to install the kernel headers into /usr/include. I used the following commands to do that: make headers_install INSTALL_HDR_PATH=/usr Some messages appeared like this: CHK include/linux/version.h make[1]: `scripts/unifdef' is up to date. REMOVE include/FlexLexer.h REMOVE include/Imlib.h REMOVE include/Imlib2.h REMOVE include/Imlib_private.h REMOVE include/Imlib_types.h REMOVE include/_G_config.h REMOVE include/a.out.h REMOVE include/aio.h ... ... ... It seems that some original headers in /usr/include was removed. My next 'make' in kernel code failed. I think the standard headers was destoried at all. I tried to install kernel headers in another Linux in another way: make headers_install cp -r usr/include/* /usr/include Then, it's ok. I wonder why the first way can cause some headers in /usr/include was removed. Mybe the kernel headers can not install directly like the first way.

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