DMA transfer within kernel space
Hi, I am new to linux device driver development and I'm trying to learn the DMA transfer. Currently I have created a DMA buffer using pci_alloc_consistent() function. Since I don't have a real DMA enabled pci device, so I am thinking of transfer the data in the DMA buffer to some other buffer within kernel space(let say created through kmalloc) using DMA. Is it possible to do DMA transfer within kernel space? If yes, please provide some sample code for the same. Thanks in advance Ravi Gupta ___ Linuxppc-dev mailing list Linuxppc-dev@lists.ozlabs.org https://lists.ozlabs.org/listinfo/linuxppc-dev
Re: kernel 2.6.33 fail to mount rootfs on ramdisk
On Tue, Aug 10, 2010 at 11:55 PM, Shawn Jin wrote: > Hi, > > The kernel 2.6.33 failed to mount the rootfs on the ramdisk. I enabled > the ramdisk block device support and ext2 filesystem as shown below. > > CONFIG_BLK_DEV_RAM=y > CONFIG_BLK_DEV_RAM_COUNT=16 > CONFIG_BLK_DEV_RAM_SIZE=4096 > CONFIG_EXT2_FS=y > > Are these adequate configurations for kernel to support rootfs on > ramdisk? What have I missed? The ramdisk image is from DENX's SELF. > The boot message is shown below. I figured that out. What I missed is CONFIG_BLK_DEV_INITRD. Thanks, -Shawn. ___ Linuxppc-dev mailing list Linuxppc-dev@lists.ozlabs.org https://lists.ozlabs.org/listinfo/linuxppc-dev
kernel version 2.6.35-git10 build failure
Hi, Today kernel(version 2.6.35-git10 -commitid 3d30701b58970) build fails with following error on both system x and p fs/9p/vfs_inode.c: In function 'v9fs_vfs_setattr_dotl': fs/9p/vfs_inode.c:1267: error: implicit declaration of function 'inode_setattr' make[2]: *** [fs/9p/vfs_inode.o] Error 1 make[2]: *** Waiting for unfinished jobs make[1]: *** [fs/9p] Error 2 make[1]: *** Waiting for unfinished jobs make: *** [fs] Error 2 make: *** Waiting for unfinished jobs Seems like the commit 87d7845aa0b is the corrupt which added the function v9fs_vfs_setattr_dotl() Thanks Divya ___ Linuxppc-dev mailing list Linuxppc-dev@lists.ozlabs.org https://lists.ozlabs.org/listinfo/linuxppc-dev
Re: kernel version 2.6.35-git10 build failure
Hi Divya, On Wed, 11 Aug 2010 12:51:35 +0530 divya wrote: > > Today kernel(version 2.6.35-git10 -commitid 3d30701b58970) build fails with > following error on both system x and p > >fs/9p/vfs_inode.c: In function 'v9fs_vfs_setattr_dotl': >fs/9p/vfs_inode.c:1267: error: implicit declaration of function > 'inode_setattr' This is known about and a fix is pending. Thanks. -- Cheers, Stephen Rothwells...@canb.auug.org.au http://www.canb.auug.org.au/~sfr/ pgp4VRhBbcbE8.pgp Description: PGP signature ___ Linuxppc-dev mailing list Linuxppc-dev@lists.ozlabs.org https://lists.ozlabs.org/listinfo/linuxppc-dev
Re: kernel version 2.6.35-git10 build failure
On Wed, 11 Aug 2010 12:51:35 +0530 divya wrote: > Hi, > > Today kernel(version 2.6.35-git10 -commitid 3d30701b58970) build fails with > following error on both system x and p > >fs/9p/vfs_inode.c: In function 'v9fs_vfs_setattr_dotl': >fs/9p/vfs_inode.c:1267: error: implicit declaration of function > 'inode_setattr' >make[2]: *** [fs/9p/vfs_inode.o] Error 1 >make[2]: *** Waiting for unfinished jobs >make[1]: *** [fs/9p] Error 2 >make[1]: *** Waiting for unfinished jobs >make: *** [fs] Error 2 >make: *** Waiting for unfinished jobs > > Seems like the commit 87d7845aa0b is the corrupt which added the function > v9fs_vfs_setattr_dotl() Yes, it is a problem I created. Stephen Rothwell has already fixed it. Al Viro has sent a git pull request to Linus today with the fix in it. Here is the patch you need: http://lkml.org/lkml/2010/6/21/442 Thanks, Sripathi. > > Thanks > Divya > > ___ Linuxppc-dev mailing list Linuxppc-dev@lists.ozlabs.org https://lists.ozlabs.org/listinfo/linuxppc-dev
Re: [PATCH] powerpc: Feature nop out reservation clear when stcx checks address
On Wed, 2010-08-11 at 16:41 +1000, Paul Mackerras wrote: > On Wed, Aug 11, 2010 at 03:20:05PM +1000, Anton Blanchard wrote: > > > All recent POWER CPUs check the address before letting the stcx succeed > > so we can create a CPU feature and nop it out. As Ben suggested, we can > > only do this in our syscall path because there is a remote possibility > > some kernel code gets interrupted by an exception that ends up operating > > on the same cacheline. > > Nice... Just one nit, and that is that I think we now need a dummy > stcx in the context switch code so there is no possibility of getting > from one user context to another with a reservation still pending from > the first context. I guess our chances of getting through schedule() > without doing any atomics, bitops or spinlocks are pretty remote, but > nevertheless it might be as well to make sure. Do we care ? IE. If we define that the moment you have done a syscall, the reservation state is undefined, we are clear here, don't you think ? Cheers, Ben. ___ Linuxppc-dev mailing list Linuxppc-dev@lists.ozlabs.org https://lists.ozlabs.org/listinfo/linuxppc-dev
Re: [PATCH] powerpc: Feature nop out reservation clear when stcx checks address
Hi Paul, > Nice... Just one nit, and that is that I think we now need a dummy > stcx in the context switch code so there is no possibility of getting > from one user context to another with a reservation still pending from > the first context. I guess our chances of getting through schedule() > without doing any atomics, bitops or spinlocks are pretty remote, but > nevertheless it might be as well to make sure. Good point. How does this look? It also swaps uses a larx in the exception exit path if we can, it's a clear win too. Anton -- [PATCH] powerpc: Feature nop out reservation clear when stcx checks address The POWER architecture does not require stcx to check that it is operating on the same address as the larx. This means it is possible for an an exception handler to execute a larx, get a reservation, decide not to do the stcx and then return back with an active reservation. If the interrupted code was in the middle of a larx/stcx sequence the stcx could incorrectly succeed. All recent POWER CPUs check the address before letting the stcx succeed so we can create a CPU feature and nop it out. As Ben suggested, we can only do this in our syscall path because there is a remote possibility some kernel code gets interrupted by an exception that ends up operating on the same cacheline. Thanks to Paul Mackerras and Derek Williams for the idea. To test this I used a very simple null syscall (actually getppid) testcase at http://ozlabs.org/~anton/junkcode/null_syscall.c I tested against 2.6.35-git10 with the following changes against the pseries_defconfig: CONFIG_VIRT_CPU_ACCOUNTING=n CONFIG_AUDIT=n CONFIG_PPC_4K_PAGES=n CONFIG_PPC_64K_PAGES=y CONFIG_FORCE_MAX_ZONEORDER=9 CONFIG_PPC_SUBPAGE_PROT=n CONFIG_FUNCTION_TRACER=n CONFIG_FUNCTION_GRAPH_TRACER=n CONFIG_IRQSOFF_TRACER=n CONFIG_STACK_TRACER=n to remove the overhead of virtual CPU accounting, syscall auditing and the ftrace mcount tracers. 64kB pages were enabled to minimise TLB misses. POWER6: +8.2% POWER7: +7.0% Another suggestion was to use a larx to something in the L1 instead of a stcx. This was almost as fast as removing the larx on POWER6, but only 3.5% faster on POWER7. We can use this to speed up the reservation clear in our exception exit code. Signed-off-by: Anton Blanchard --- Index: powerpc.git/arch/powerpc/kernel/entry_64.S === --- powerpc.git.orig/arch/powerpc/kernel/entry_64.S 2010-08-11 21:04:52.644491970 +1000 +++ powerpc.git/arch/powerpc/kernel/entry_64.S 2010-08-11 21:13:46.210740998 +1000 @@ -202,7 +202,9 @@ syscall_exit: bge-syscall_error syscall_error_cont: ld r7,_NIP(r1) +BEGIN_FTR_SECTION stdcx. r0,0,r1 /* to clear the reservation */ +END_FTR_SECTION_IFCLR(CPU_FTR_STCX_CHECKS_ADDRESS) andi. r6,r8,MSR_PR ld r4,_LINK(r1) /* @@ -419,6 +421,17 @@ END_FTR_SECTION_IFSET(CPU_FTR_ALTIVEC) sync #endif /* CONFIG_SMP */ + /* +* If we optimise away the clear of the reservation in system +* calls because we know the CPU tracks the address of the +* reservation, then we need to clear it here to cover the +* case that the kernel context switch path has no larx +* instructions. +*/ +BEGIN_FTR_SECTION + ldarx r6,0,r1 +END_FTR_SECTION_IFSET(CPU_FTR_STCX_CHECKS_ADDRESS) + addir6,r4,-THREAD /* Convert THREAD to 'current' */ std r6,PACACURRENT(r13) /* Set new 'current' */ @@ -576,7 +589,16 @@ ALT_FW_FTR_SECTION_END_IFCLR(FW_FEATURE_ andi. r0,r3,MSR_RI beq-unrecov_restore + /* +* Clear the reservation. If we know the CPU tracks the address of +* the reservation then we can potentially save some cycles and use +* a larx. On POWER6 and POWER7 this is significantly faster. +*/ +BEGIN_FTR_SECTION stdcx. r0,0,r1 /* to clear the reservation */ +FTR_SECTION_ELSE + ldarx r4,0,r1 +ALT_FTR_SECTION_END_IFCLR(CPU_FTR_STCX_CHECKS_ADDRESS) /* * Clear RI before restoring r13. If we are returning to Index: powerpc.git/arch/powerpc/include/asm/cputable.h === --- powerpc.git.orig/arch/powerpc/include/asm/cputable.h2010-08-11 21:04:52.614491766 +1000 +++ powerpc.git/arch/powerpc/include/asm/cputable.h 2010-08-11 21:13:14.190741348 +1000 @@ -198,6 +198,7 @@ extern const char *powerpc_base_platform #define CPU_FTR_CP_USE_DCBTZ LONG_ASM_CONST(0x0040) #define CPU_FTR_UNALIGNED_LD_STD LONG_ASM_CONST(0x0080) #define CPU_FTR_ASYM_SMT LONG_ASM_CONST(0x0100) +#define CPU_FTR_STCX_CHECKS_ADDRESSLONG_ASM_CONST(0x0200) #ifndef __ASSEMBLY__ @@ -392,28 +393,31 @@ extern const char *powerpc_base_platform CPU_FTR_MMCRA | CPU_FTR_CTRL)
Re: kernel version 2.6.35-git10 build failure
On 11.08.2010 09:53, Sripathi Kodi wrote:
On Wed, 11 Aug 2010 12:51:35 +0530
divya wrote:
Hi,
Today kernel(version 2.6.35-git10 -commitid 3d30701b58970) build fails with
following error on both system x and p
fs/9p/vfs_inode.c: In function 'v9fs_vfs_setattr_dotl':
fs/9p/vfs_inode.c:1267: error: implicit declaration of function
'inode_setattr'
make[2]: *** [fs/9p/vfs_inode.o] Error 1
make[2]: *** Waiting for unfinished jobs
make[1]: *** [fs/9p] Error 2
make[1]: *** Waiting for unfinished jobs
make: *** [fs] Error 2
make: *** Waiting for unfinished jobs
Seems like the commit 87d7845aa0b is the corrupt which added the function
v9fs_vfs_setattr_dotl()
Yes, it is a problem I created. Stephen Rothwell has already fixed it.
Al Viro has sent a git pull request to Linus today with the fix in it.
Here is the patch you need: http://lkml.org/lkml/2010/6/21/442
I fail to apply the patch.
aapi205:/usr/src/linux# patch -p1 < ../9p-patch.txt
patching file fs/9p/vfs_inode.c
Hunk #1 FAILED at 1052.
1 out of 1 hunk FAILED -- saving rejects to file fs/9p/vfs_inode.c.rej
aapi205:/usr/src/linux# cat fs/9p/vfs_inode.c.rej
--- fs/9p/vfs_inode.c
+++ fs/9p/vfs_inode.c
@@ -1052,10 +1052,19 @@
return PTR_ERR(fid);
retval = p9_client_setattr(fid, &p9attr);
- if (retval >= 0)
- retval = inode_setattr(dentry->d_inode, iattr);
+ if (retval < 0)
+ return retval;
- return retval;
+ if ((iattr->ia_valid & ATTR_SIZE) &&
+ iattr->ia_size != i_size_read(dentry->d_inode)) {
+ retval = vmtruncate(dentry->d_inode, iattr->ia_size);
+ if (retval)
+ return retval;
+ }
+
+ setattr_copy(dentry->d_inode, iattr);
+ mark_inode_dirty(dentry->d_inode);
+ return 0;
}
/**
I must be doing something wrong way.
Regards,
Piotr Hosowicz
--
Z cyklu "Uroki demokracji", czyli pytania i odpowiedzi w teledurniejach:
- Jaką walutę mają Indie?
- Ramadan.
NP: Patrick O'Hearn - Approaching Summit
NB: 2.6.35-git9
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How to use mpc8xxx_gpio.c device driver
Hi,
I am new to device driver development. I am trying to access the GPIO of
MPC837xERDB eval board. I have upgraded its kernel to linux-2.6.28.9 and
enable support for mpc8xxx_gpio.c. On boot up, it successfully detect two
gpio controllers. Now my question is how I am going to use it to communicate
with the gpio pins? Do I have to modify the code in mpc8xxx_gpio.c file to
do whatever I want to do with gpios or I can use the standard gpio API
provided in kernel ( gpio_request()/gpio_free() ). I also tries the standard
kernel API, but it fails. Here is my code :
#include
#include /* error codes */
#include
static __init int sample_module_init(void)
{
int ret;
int i;
for (i=1; i<32; i++) {
ret = gpio_request(i, "Sample Driver");
if (ret) {
printk(KERN_WARNING "sample_driver: unable to request GPIO_PG%d\n",
i);
//return ret;
}
}
return 0;
}
static __exit void sample_module_exit(void)
{
gpio_free(9);
}
MODULE_LICENSE("GPL");
module_init(sample_module_init);
module_exit(sample_module_exit);
It give the following O/P:
[ 617.075329] sample_driver: unable to request GPIO_PG1
[ 617.080418] sample_driver: unable to request GPIO_PG2
[ 617.085470] sample_driver: unable to request GPIO_PG3
[ 617.090522] sample_driver: unable to request GPIO_PG4
[ 617.095574] sample_driver: unable to request GPIO_PG5
[ 617.100625] sample_driver: unable to request GPIO_PG6
[ 617.105676] sample_driver: unable to request GPIO_PG7
[ 617.110727] sample_driver: unable to request GPIO_PG8
[ 617.115779] sample_driver: unable to request GPIO_PG9
[ 617.120830] sample_driver: unable to request GPIO_PG10
[ 617.125968] sample_driver: unable to request GPIO_PG11
[ 617.131106] sample_driver: unable to request GPIO_PG12
[ 617.136245] sample_driver: unable to request GPIO_PG13
[ 617.141383] sample_driver: unable to request GPIO_PG14
[ 617.146521] sample_driver: unable to request GPIO_PG15
[ 617.151660] sample_driver: unable to request GPIO_PG16
[ 617.156798] sample_driver: unable to request GPIO_PG17
[ 617.161936] sample_driver: unable to request GPIO_PG18
[ 617.167074] sample_driver: unable to request GPIO_PG19
[ 617.172213] sample_driver: unable to request GPIO_PG20
[ 617.177351] sample_driver: unable to request GPIO_PG21
[ 617.182489] sample_driver: unable to request GPIO_PG22
[ 617.187628] sample_driver: unable to request GPIO_PG23
[ 617.192767] sample_driver: unable to request GPIO_PG24
[ 617.197905] sample_driver: unable to request GPIO_PG25
[ 617.203042] sample_driver: unable to request GPIO_PG26
[ 617.208182] sample_driver: unable to request GPIO_PG27
[ 617.213319] sample_driver: unable to request GPIO_PG28
[ 617.218458] sample_driver: unable to request GPIO_PG29
[ 617.223597] sample_driver: unable to request GPIO_PG30
[ 617.228735] sample_driver: unable to request GPIO_PG31
[ 617.233873] sample_driver: unable to request GPIO_PG32
Can someone provide me a sample code or something else. Actually I am trying
to set the GPIO pin no. 9 to active low as it is connected to a LED on
board.
Thanks in advance
Ravi Gupta
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Re: [PATCH 0/8] v5 De-couple sysfs memory directories from memory sections
On Mon, 2010-08-09 at 12:53 -0500, Nathan Fontenot wrote: > This set of patches de-couples the idea that there is a single > directory in sysfs for each memory section. The intent of the > patches is to reduce the number of sysfs directories created to > resolve a boot-time performance issue. On very large systems > boot time are getting very long (as seen on powerpc hardware) > due to the enormous number of sysfs directories being created. > On a system with 1 TB of memory we create ~63,000 directories. > For even larger systems boot times are being measured in hours. Hi Nathan, The set is looking pretty good to me. We _might_ want to up the ante in the future and allow it to be even more dynamic than this, but this looks like a good start to me. BTW, have you taken a look at what the hotplug events look like if only a single section (not filling up a whole block) is added? Feel free to add my: Acked-by: Dave Hansen -- Dave ___ Linuxppc-dev mailing list Linuxppc-dev@lists.ozlabs.org https://lists.ozlabs.org/listinfo/linuxppc-dev
Re: How to use mpc8xxx_gpio.c device driver
u can directly access GPIO registers in kernel, by ioremap of GPIO
memory mapped registers.
you might need to check
- muxing of gpio
-mj
On Wed, Aug 11, 2010 at 6:57 PM, Ravi Gupta wrote:
> Hi,
>
> I am new to device driver development. I am trying to access the GPIO of
> MPC837xERDB eval board. I have upgraded its kernel to linux-2.6.28.9 and
> enable support for mpc8xxx_gpio.c. On boot up, it successfully detect two
> gpio controllers. Now my question is how I am going to use it to communicate
> with the gpio pins? Do I have to modify the code in mpc8xxx_gpio.c file to
> do whatever I want to do with gpios or I can use the standard gpio API
> provided in kernel ( gpio_request()/gpio_free() ). I also tries the standard
> kernel API, but it fails. Here is my code :
>
> #include
> #include /* error codes */
> #include
>
> static __init int sample_module_init(void)
> {
> int ret;
>
> int i;
> for (i=1; i<32; i++) {
> ret = gpio_request(i, "Sample Driver");
> if (ret) {
> printk(KERN_WARNING "sample_driver: unable to request GPIO_PG%d\n",
> i);
> //return ret;
> }
> }
>
> return 0;
> }
>
> static __exit void sample_module_exit(void)
> {
> gpio_free(9);
> }
>
> MODULE_LICENSE("GPL");
>
> module_init(sample_module_init);
> module_exit(sample_module_exit);
>
> It give the following O/P:
>
> [ 617.075329] sample_driver: unable to request GPIO_PG1
> [ 617.080418] sample_driver: unable to request GPIO_PG2
> [ 617.085470] sample_driver: unable to request GPIO_PG3
> [ 617.090522] sample_driver: unable to request GPIO_PG4
> [ 617.095574] sample_driver: unable to request GPIO_PG5
> [ 617.100625] sample_driver: unable to request GPIO_PG6
> [ 617.105676] sample_driver: unable to request GPIO_PG7
> [ 617.110727] sample_driver: unable to request GPIO_PG8
> [ 617.115779] sample_driver: unable to request GPIO_PG9
> [ 617.120830] sample_driver: unable to request GPIO_PG10
> [ 617.125968] sample_driver: unable to request GPIO_PG11
> [ 617.131106] sample_driver: unable to request GPIO_PG12
> [ 617.136245] sample_driver: unable to request GPIO_PG13
> [ 617.141383] sample_driver: unable to request GPIO_PG14
> [ 617.146521] sample_driver: unable to request GPIO_PG15
> [ 617.151660] sample_driver: unable to request GPIO_PG16
> [ 617.156798] sample_driver: unable to request GPIO_PG17
> [ 617.161936] sample_driver: unable to request GPIO_PG18
> [ 617.167074] sample_driver: unable to request GPIO_PG19
> [ 617.172213] sample_driver: unable to request GPIO_PG20
> [ 617.177351] sample_driver: unable to request GPIO_PG21
> [ 617.182489] sample_driver: unable to request GPIO_PG22
> [ 617.187628] sample_driver: unable to request GPIO_PG23
> [ 617.192767] sample_driver: unable to request GPIO_PG24
> [ 617.197905] sample_driver: unable to request GPIO_PG25
> [ 617.203042] sample_driver: unable to request GPIO_PG26
> [ 617.208182] sample_driver: unable to request GPIO_PG27
> [ 617.213319] sample_driver: unable to request GPIO_PG28
> [ 617.218458] sample_driver: unable to request GPIO_PG29
> [ 617.223597] sample_driver: unable to request GPIO_PG30
> [ 617.228735] sample_driver: unable to request GPIO_PG31
> [ 617.233873] sample_driver: unable to request GPIO_PG32
>
> Can someone provide me a sample code or something else. Actually I am trying
> to set the GPIO pin no. 9 to active low as it is connected to a LED on
> board.
>
> Thanks in advance
> Ravi Gupta
>
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>
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Re: How to use mpc8xxx_gpio.c device driver
Also, when I try to export a gpio in sysfs echo 9 > /sys/class/gpio/export It gives me an error in dmesg gpio_request: gpio-9 (sysfs) status -22 export_store: status -22 Here is a look of sysfs on my machine # ls /sys/class/gpio/ -la drwxr-xr-x4 root root0 Jan 1 00:00 . drwxr-xr-x 24 root root0 Jan 1 00:00 .. --w---1 root root 4096 Jan 1 00:10 export drwxr-xr-x3 root root0 Jan 1 00:00 gpiochip192 drwxr-xr-x3 root root0 Jan 1 00:00 gpiochip224 --w---1 root root 4096 Jan 1 00:00 unexport ___ Linuxppc-dev mailing list Linuxppc-dev@lists.ozlabs.org https://lists.ozlabs.org/listinfo/linuxppc-dev
Re: How to use mpc8xxx_gpio.c device driver
Hi,
On Wed, Aug 11, 2010 at 06:57:16PM +0530, Ravi Gupta wrote:
> I am new to device driver development. I am trying to access the GPIO of
> MPC837xERDB eval board. I have upgraded its kernel to linux-2.6.28.9 and
> enable support for mpc8xxx_gpio.c. On boot up, it successfully detect two
> gpio controllers. Now my question is how I am going to use it to communicate
> with the gpio pins? Do I have to modify the code in mpc8xxx_gpio.c file to
> do whatever I want to do with gpios or I can use the standard gpio API
> provided in kernel ( gpio_request()/gpio_free() ). I also tries the standard
> kernel API, but it fails. Here is my code :
No, you don't have to modify anything, and yes, you can
use standard kernel GPIO API.
> #include
> #include /* error codes */
> #include
>
> static __init int sample_module_init(void)
> {
> int ret;
>
> int i;
> for (i=1; i<32; i++) {
> ret = gpio_request(i, "Sample Driver");
Before issing gpio_request() you must get GPIO number from the
of_get_gpio() or of_get_gpio_flags() calls (the _flags variant
will also retreive flags such as 'active-low').
The calls assume that you have gpio = <> specifier in the
device tree, see arch/powerpc/boot/dts/mpc8377_rdb.dts's
"leds" node as an example.
As you want GPIO LEDs, you can use drivers/leds/leds-gpio.c
(see of_gpio_leds_probe() call, it gets gpio numbers via
of_get_gpio_flags() and then requests them via gpio_request()).
Also see
Documentation/powerpc/dts-bindings/gpio/gpio.txt
Documentation/powerpc/dts-bindings/gpio/led.txt
> if (ret) {
> printk(KERN_WARNING "sample_driver: unable to request GPIO_PG%d\n",
> i);
> //return ret;
> }
> }
>
> return 0;
> }
On Wed, Aug 11, 2010 at 07:49:40PM +0530, Ravi Gupta wrote:
> Also, when I try to export a gpio in sysfs
>
> echo 9 > /sys/class/gpio/export
The gpio numbers are global, i.e. GPIO controller base + GPIO
number within the controller.
[...]
> drwxr-xr-x3 root root0 Jan 1 00:00 gpiochip192
So, if you want GPIO9 within gpiochip192, you should issue
"echo 201 > export".
Thanks,
--
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email: cbouatmai...@gmail.com
irc://irc.freenode.net/bd2
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Re: How to use mpc8xxx_gpio.c device driver
On Wed, Aug 11, 2010 at 07:49:40PM +0530, Ravi Gupta wrote: > Also, when I try to export a gpio in sysfs > > echo 9 > /sys/class/gpio/export > > It gives me an error in dmesg > gpio_request: gpio-9 (sysfs) status -22 > export_store: status -22 > > Here is a look of sysfs on my machine > > # ls /sys/class/gpio/ -la > drwxr-xr-x4 root root0 Jan 1 00:00 . > drwxr-xr-x 24 root root0 Jan 1 00:00 .. > --w---1 root root 4096 Jan 1 00:10 export > drwxr-xr-x3 root root0 Jan 1 00:00 gpiochip192 > drwxr-xr-x3 root root0 Jan 1 00:00 gpiochip224 > --w---1 root root 4096 Jan 1 00:00 unexport Your GPIO pins are numbered from 192-223 on one GPIO chip, and 224-255 on the next GPIO chip. You should be exporting GPIO pin 200 or 201 (192+8 or 192+9), depending on whether your pins are numbered from zero or one. "status -22" is -EINVAL: Invalid Argument. You're doing something which is invalid, so this makes sense. There is no "pin 9". Ira ___ Linuxppc-dev mailing list Linuxppc-dev@lists.ozlabs.org https://lists.ozlabs.org/listinfo/linuxppc-dev
[PATCH] booting-without-of: Remove nonexistent chapters from TOC, fix numbering
Marvell and GPIO bindings live in their own files, so the TOC should not mention them. Also fix chapters numbering. Signed-off-by: Anton Vorontsov --- Documentation/powerpc/booting-without-of.txt | 31 + 1 files changed, 2 insertions(+), 29 deletions(-) diff --git a/Documentation/powerpc/booting-without-of.txt b/Documentation/powerpc/booting-without-of.txt index 46d2210..3f454b7 100644 --- a/Documentation/powerpc/booting-without-of.txt +++ b/Documentation/powerpc/booting-without-of.txt @@ -49,40 +49,13 @@ Table of Contents f) MDIO on GPIOs g) SPI busses - VII - Marvell Discovery mv64[345]6x System Controller chips -1) The /system-controller node -2) Child nodes of /system-controller - a) Marvell Discovery MDIO bus - b) Marvell Discovery ethernet controller - c) Marvell Discovery PHY nodes - d) Marvell Discovery SDMA nodes - e) Marvell Discovery BRG nodes - f) Marvell Discovery CUNIT nodes - g) Marvell Discovery MPSCROUTING nodes - h) Marvell Discovery MPSCINTR nodes - i) Marvell Discovery MPSC nodes - j) Marvell Discovery Watch Dog Timer nodes - k) Marvell Discovery I2C nodes - l) Marvell Discovery PIC (Programmable Interrupt Controller) nodes - m) Marvell Discovery MPP (Multipurpose Pins) multiplexing nodes - n) Marvell Discovery GPP (General Purpose Pins) nodes - o) Marvell Discovery PCI host bridge node - p) Marvell Discovery CPU Error nodes - q) Marvell Discovery SRAM Controller nodes - r) Marvell Discovery PCI Error Handler nodes - s) Marvell Discovery Memory Controller nodes - - VIII - Specifying interrupt information for devices + VII - Specifying interrupt information for devices 1) interrupts property 2) interrupt-parent property 3) OpenPIC Interrupt Controllers 4) ISA Interrupt Controllers - IX - Specifying GPIO information for devices -1) gpios property -2) gpio-controller nodes - - X - Specifying device power management information (sleep property) + VIII - Specifying device power management information (sleep property) Appendix A - Sample SOC node for MPC8540 -- 1.7.0.5 ___ Linuxppc-dev mailing list Linuxppc-dev@lists.ozlabs.org https://lists.ozlabs.org/listinfo/linuxppc-dev
[PATCH 1/1] powerpc: Clear cpu_sibling_map in cpu_die
While testing CPU DLPAR, the following problem was discovered.
We were DLPAR removing the first CPU, which in this case was
logical CPUs 0-3. CPUs 0-2 were already marked offline and
we were in the process of offlining CPU 3. After marking
the CPU inactive and offline in cpu_disable, but before the
cpu was completely idle (cpu_die), we ended up in __make_request
on CPU 3. There we looked at the topology map to see which CPU
to complete the I/O on and found no CPUs in the cpu_sibling_map.
This resulted in the block layer setting the completion cpu
to be NR_CPUS, which then caused an oops when we tried to
complete the I/O.
Fix this by delaying clearing the sibling map of the cpu we
are offlining for the cpu we are offlining until cpu_die.
Signed-off-by: Brian King
---
arch/powerpc/kernel/smp.c |9 +++--
1 file changed, 7 insertions(+), 2 deletions(-)
diff -puN arch/powerpc/kernel/smp.c~powerpc_sibling_map_offline
arch/powerpc/kernel/smp.c
--- linux-2.6/arch/powerpc/kernel/smp.c~powerpc_sibling_map_offline
2010-08-09 16:49:47.0 -0500
+++ linux-2.6-bjking1/arch/powerpc/kernel/smp.c 2010-08-09 16:49:47.0
-0500
@@ -598,8 +598,11 @@ int __cpu_disable(void)
/* Update sibling maps */
base = cpu_first_thread_in_core(cpu);
for (i = 0; i < threads_per_core; i++) {
- cpumask_clear_cpu(cpu, cpu_sibling_mask(base + i));
- cpumask_clear_cpu(base + i, cpu_sibling_mask(cpu));
+ if ((base + i) != cpu) {
+ cpumask_clear_cpu(cpu, cpu_sibling_mask(base + i));
+ cpumask_clear_cpu(base + i, cpu_sibling_mask(cpu));
+ }
+
cpumask_clear_cpu(cpu, cpu_core_mask(base + i));
cpumask_clear_cpu(base + i, cpu_core_mask(cpu));
}
@@ -641,6 +644,8 @@ void cpu_hotplug_driver_unlock()
void cpu_die(void)
{
+ cpumask_clear_cpu(smp_processor_id(),
cpu_sibling_mask(smp_processor_id()));
+
if (ppc_md.cpu_die)
ppc_md.cpu_die();
}
_
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[039/111] irq: Add new IRQ flag IRQF_NO_SUSPEND
2.6.32-stable review patch. If anyone has any objections, please let us know.
--
From: Ian Campbell
commit 685fd0b4ea3f0f1d5385610b0d5b57775a8d5842 upstream.
A small number of users of IRQF_TIMER are using it for the implied no
suspend behaviour on interrupts which are not timer interrupts.
Therefore add a new IRQF_NO_SUSPEND flag, rename IRQF_TIMER to
__IRQF_TIMER and redefine IRQF_TIMER in terms of these new flags.
Signed-off-by: Ian Campbell
Cc: Jeremy Fitzhardinge
Cc: Dmitry Torokhov
Cc: Benjamin Herrenschmidt
Cc: Paul Mackerras
Cc: Grant Likely
Cc: xen-de...@lists.xensource.com
Cc: linux-in...@vger.kernel.org
Cc: linuxppc-...@ozlabs.org
Cc: devicetree-disc...@lists.ozlabs.org
LKML-Reference: <1280398595-29708-1-git-send-email-ian.campb...@citrix.com>
Signed-off-by: Thomas Gleixner
Signed-off-by: Greg Kroah-Hartman
---
include/linux/interrupt.h |7 ++-
kernel/irq/manage.c |2 +-
2 files changed, 7 insertions(+), 2 deletions(-)
--- a/include/linux/interrupt.h
+++ b/include/linux/interrupt.h
@@ -52,16 +52,21 @@
* IRQF_ONESHOT - Interrupt is not reenabled after the hardirq handler
finished.
*Used by threaded interrupts which need to keep the
*irq line disabled until the threaded handler has been run.
+ * IRQF_NO_SUSPEND - Do not disable this IRQ during suspend
+ *
*/
#define IRQF_DISABLED 0x0020
#define IRQF_SAMPLE_RANDOM 0x0040
#define IRQF_SHARED0x0080
#define IRQF_PROBE_SHARED 0x0100
-#define IRQF_TIMER 0x0200
+#define __IRQF_TIMER 0x0200
#define IRQF_PERCPU0x0400
#define IRQF_NOBALANCING 0x0800
#define IRQF_IRQPOLL 0x1000
#define IRQF_ONESHOT 0x2000
+#define IRQF_NO_SUSPEND0x4000
+
+#define IRQF_TIMER (__IRQF_TIMER | IRQF_NO_SUSPEND)
/*
* Bits used by threaded handlers:
--- a/kernel/irq/manage.c
+++ b/kernel/irq/manage.c
@@ -200,7 +200,7 @@ static inline int setup_affinity(unsigne
void __disable_irq(struct irq_desc *desc, unsigned int irq, bool suspend)
{
if (suspend) {
- if (!desc->action || (desc->action->flags & IRQF_TIMER))
+ if (!desc->action || (desc->action->flags & IRQF_NO_SUSPEND))
return;
desc->status |= IRQ_SUSPENDED;
}
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[48/54] irq: Add new IRQ flag IRQF_NO_SUSPEND
2.6.34-stable review patch. If anyone has any objections, please let us know.
--
From: Ian Campbell
commit 685fd0b4ea3f0f1d5385610b0d5b57775a8d5842 upstream.
A small number of users of IRQF_TIMER are using it for the implied no
suspend behaviour on interrupts which are not timer interrupts.
Therefore add a new IRQF_NO_SUSPEND flag, rename IRQF_TIMER to
__IRQF_TIMER and redefine IRQF_TIMER in terms of these new flags.
Signed-off-by: Ian Campbell
Cc: Jeremy Fitzhardinge
Cc: Dmitry Torokhov
Cc: Benjamin Herrenschmidt
Cc: Paul Mackerras
Cc: Grant Likely
Cc: xen-de...@lists.xensource.com
Cc: linux-in...@vger.kernel.org
Cc: linuxppc-...@ozlabs.org
Cc: devicetree-disc...@lists.ozlabs.org
LKML-Reference: <1280398595-29708-1-git-send-email-ian.campb...@citrix.com>
Signed-off-by: Thomas Gleixner
Signed-off-by: Greg Kroah-Hartman
---
include/linux/interrupt.h |7 ++-
kernel/irq/manage.c |2 +-
2 files changed, 7 insertions(+), 2 deletions(-)
--- a/include/linux/interrupt.h
+++ b/include/linux/interrupt.h
@@ -52,16 +52,21 @@
* IRQF_ONESHOT - Interrupt is not reenabled after the hardirq handler
finished.
*Used by threaded interrupts which need to keep the
*irq line disabled until the threaded handler has been run.
+ * IRQF_NO_SUSPEND - Do not disable this IRQ during suspend
+ *
*/
#define IRQF_DISABLED 0x0020
#define IRQF_SAMPLE_RANDOM 0x0040
#define IRQF_SHARED0x0080
#define IRQF_PROBE_SHARED 0x0100
-#define IRQF_TIMER 0x0200
+#define __IRQF_TIMER 0x0200
#define IRQF_PERCPU0x0400
#define IRQF_NOBALANCING 0x0800
#define IRQF_IRQPOLL 0x1000
#define IRQF_ONESHOT 0x2000
+#define IRQF_NO_SUSPEND0x4000
+
+#define IRQF_TIMER (__IRQF_TIMER | IRQF_NO_SUSPEND)
/*
* Bits used by threaded handlers:
--- a/kernel/irq/manage.c
+++ b/kernel/irq/manage.c
@@ -200,7 +200,7 @@ static inline int setup_affinity(unsigne
void __disable_irq(struct irq_desc *desc, unsigned int irq, bool suspend)
{
if (suspend) {
- if (!desc->action || (desc->action->flags & IRQF_TIMER))
+ if (!desc->action || (desc->action->flags & IRQF_NO_SUSPEND))
return;
desc->status |= IRQ_SUSPENDED;
}
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[64/67] irq: Add new IRQ flag IRQF_NO_SUSPEND
2.6.35-stable review patch. If anyone has any objections, please let us know.
--
From: Ian Campbell
commit 685fd0b4ea3f0f1d5385610b0d5b57775a8d5842 upstream.
A small number of users of IRQF_TIMER are using it for the implied no
suspend behaviour on interrupts which are not timer interrupts.
Therefore add a new IRQF_NO_SUSPEND flag, rename IRQF_TIMER to
__IRQF_TIMER and redefine IRQF_TIMER in terms of these new flags.
Signed-off-by: Ian Campbell
Cc: Jeremy Fitzhardinge
Cc: Dmitry Torokhov
Cc: Benjamin Herrenschmidt
Cc: Paul Mackerras
Cc: Grant Likely
Cc: xen-de...@lists.xensource.com
Cc: linux-in...@vger.kernel.org
Cc: linuxppc-...@ozlabs.org
Cc: devicetree-disc...@lists.ozlabs.org
LKML-Reference: <1280398595-29708-1-git-send-email-ian.campb...@citrix.com>
Signed-off-by: Thomas Gleixner
Signed-off-by: Greg Kroah-Hartman
---
include/linux/interrupt.h |7 ++-
kernel/irq/manage.c |2 +-
2 files changed, 7 insertions(+), 2 deletions(-)
--- a/include/linux/interrupt.h
+++ b/include/linux/interrupt.h
@@ -53,16 +53,21 @@
* IRQF_ONESHOT - Interrupt is not reenabled after the hardirq handler
finished.
*Used by threaded interrupts which need to keep the
*irq line disabled until the threaded handler has been run.
+ * IRQF_NO_SUSPEND - Do not disable this IRQ during suspend
+ *
*/
#define IRQF_DISABLED 0x0020
#define IRQF_SAMPLE_RANDOM 0x0040
#define IRQF_SHARED0x0080
#define IRQF_PROBE_SHARED 0x0100
-#define IRQF_TIMER 0x0200
+#define __IRQF_TIMER 0x0200
#define IRQF_PERCPU0x0400
#define IRQF_NOBALANCING 0x0800
#define IRQF_IRQPOLL 0x1000
#define IRQF_ONESHOT 0x2000
+#define IRQF_NO_SUSPEND0x4000
+
+#define IRQF_TIMER (__IRQF_TIMER | IRQF_NO_SUSPEND)
/*
* Bits used by threaded handlers:
--- a/kernel/irq/manage.c
+++ b/kernel/irq/manage.c
@@ -216,7 +216,7 @@ static inline int setup_affinity(unsigne
void __disable_irq(struct irq_desc *desc, unsigned int irq, bool suspend)
{
if (suspend) {
- if (!desc->action || (desc->action->flags & IRQF_TIMER))
+ if (!desc->action || (desc->action->flags & IRQF_NO_SUSPEND))
return;
desc->status |= IRQ_SUSPENDED;
}
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[PATCH] powerpc: Fix bogus it_blocksize in VIO iommu code
When looking at some issues with the virtual ethernet driver I noticed
that TCE allocation was following a very strange pattern:
address 00e9000 length 2048
address 0409000 length 2048 <-
address 0429000 length 2048
address 0449000 length 2048
address 0469000 length 2048
address 0489000 length 2048
address 04a9000 length 2048
address 04c9000 length 2048
address 04e9000 length 2048
address 4009000 length 2048 <-
address 4029000 length 2048
Huge unexplained gaps in what should be an empty TCE table. It turns out
it_blocksize, the amount we want to align the next allocation to, was
c000fe903b20. Completely bogus.
Initialise it to something reasonable in the VIO IOMMU code, and use kzalloc
everywhere to protect against this when we next add a non compulsary
field to iommu code and forget to initialise it.
Signed-off-by: Anton Blanchard
---
Index: powerpc.git/arch/powerpc/kernel/vio.c
===
--- powerpc.git.orig/arch/powerpc/kernel/vio.c 2010-08-12 12:27:58.674490962
+1000
+++ powerpc.git/arch/powerpc/kernel/vio.c 2010-08-12 12:28:18.660741428
+1000
@@ -1059,7 +1059,7 @@ static struct iommu_table *vio_build_iom
if (!dma_window)
return NULL;
- tbl = kmalloc(sizeof(*tbl), GFP_KERNEL);
+ tbl = kzalloc(sizeof(*tbl), GFP_KERNEL);
if (tbl == NULL)
return NULL;
@@ -1072,6 +1072,7 @@ static struct iommu_table *vio_build_iom
tbl->it_offset = offset >> IOMMU_PAGE_SHIFT;
tbl->it_busno = 0;
tbl->it_type = TCE_VB;
+ tbl->it_blocksize = 16;
return iommu_init_table(tbl, -1);
}
Index: powerpc.git/arch/powerpc/platforms/iseries/iommu.c
===
--- powerpc.git.orig/arch/powerpc/platforms/iseries/iommu.c 2010-08-12
12:29:35.473241172 +1000
+++ powerpc.git/arch/powerpc/platforms/iseries/iommu.c 2010-08-12
12:29:50.190890563 +1000
@@ -184,7 +184,7 @@ static void pci_dma_dev_setup_iseries(st
BUG_ON(lsn == NULL);
- tbl = kmalloc(sizeof(struct iommu_table), GFP_KERNEL);
+ tbl = kzalloc(sizeof(struct iommu_table), GFP_KERNEL);
iommu_table_getparms_iSeries(pdn->busno, *lsn, 0, tbl);
Index: powerpc.git/arch/powerpc/platforms/pseries/iommu.c
===
--- powerpc.git.orig/arch/powerpc/platforms/pseries/iommu.c 2010-08-12
12:28:45.340756738 +1000
+++ powerpc.git/arch/powerpc/platforms/pseries/iommu.c 2010-08-12
12:29:15.401118951 +1000
@@ -403,7 +403,7 @@ static void pci_dma_bus_setup_pSeries(st
pci->phb->dma_window_size = 0x800ul;
pci->phb->dma_window_base_cur = 0x800ul;
- tbl = kmalloc_node(sizeof(struct iommu_table), GFP_KERNEL,
+ tbl = kzalloc_node(sizeof(struct iommu_table), GFP_KERNEL,
pci->phb->node);
iommu_table_setparms(pci->phb, dn, tbl);
@@ -448,7 +448,7 @@ static void pci_dma_bus_setup_pSeriesLP(
pdn->full_name, ppci->iommu_table);
if (!ppci->iommu_table) {
- tbl = kmalloc_node(sizeof(struct iommu_table), GFP_KERNEL,
+ tbl = kzalloc_node(sizeof(struct iommu_table), GFP_KERNEL,
ppci->phb->node);
iommu_table_setparms_lpar(ppci->phb, pdn, tbl, dma_window,
bus->number);
@@ -478,7 +478,7 @@ static void pci_dma_dev_setup_pSeries(st
struct pci_controller *phb = PCI_DN(dn)->phb;
pr_debug(" --> first child, no bridge. Allocating iommu
table.\n");
- tbl = kmalloc_node(sizeof(struct iommu_table), GFP_KERNEL,
+ tbl = kzalloc_node(sizeof(struct iommu_table), GFP_KERNEL,
phb->node);
iommu_table_setparms(phb, dn, tbl);
PCI_DN(dn)->iommu_table = iommu_init_table(tbl, phb->node);
@@ -544,7 +544,7 @@ static void pci_dma_dev_setup_pSeriesLP(
pci = PCI_DN(pdn);
if (!pci->iommu_table) {
- tbl = kmalloc_node(sizeof(struct iommu_table), GFP_KERNEL,
+ tbl = kzalloc_node(sizeof(struct iommu_table), GFP_KERNEL,
pci->phb->node);
iommu_table_setparms_lpar(pci->phb, pdn, tbl, dma_window,
pci->phb->bus->number);
Index: powerpc.git/arch/powerpc/platforms/cell/iommu.c
===
--- powerpc.git.orig/arch/powerpc/platforms/cell/iommu.c2010-08-12
12:31:27.040741891 +1000
+++ powerpc.git/arch/powerpc/platforms/cell/iommu.c 2010-08-12
12:31:34.641324320 +1000
@@ -477,7 +477,7 @@ cell_iommu_setup_window(struct cbe_iommu
ioid = cell_iommu_get_ioid(np);
- window = kmalloc_node(sizeof(*window), GFP_KERNEL, iommu->nid);
+ window = kzalloc_node(sizeof(*window), GFP_KERNEL,
RE: [PATCH 1/2] mmc: change ACMD12 to AUTO_CMD12 for more clear
> -Original Message- > From: Zang Roy-R61911 > Sent: Wednesday, August 11, 2010 12:47 PM > To: Zang Roy-R61911; a...@linux-foundation.org; > linux-...@vger.kernel.org > Cc: linuxppc-...@ozlabs.org; mir...@gmail.com; > cbouatmai...@gmail.com; grant.lik...@secretlab.ca > Subject: RE: [PATCH 1/2] mmc: change ACMD12 to AUTO_CMD12 for > more clear > > > > > -Original Message- > > From: Zang Roy-R61911 > > Sent: Tuesday, August 10, 2010 17:47 PM > > To: a...@linux-foundation.org; linux-...@vger.kernel.org > > Cc: linuxppc-...@ozlabs.org; mir...@gmail.com; > > cbouatmai...@gmail.com; grant.lik...@secretlab.ca > > Subject: [PATCH 1/2] mmc: change ACMD12 to AUTO_CMD12 for more clear > > > > Change ACMD12 to AUTO_CMD12 to reduce the confusion. > > ACMD12 might be confused with MMC/SD App CMD 12 (CMD55+CMD12 combo). > > > > Signed-off-by: Roy Zang > > --- > > drivers/mmc/host/sdhci-of-core.c |2 +- > > drivers/mmc/host/sdhci.c |8 > > drivers/mmc/host/sdhci.h | 10 +- > > 3 files changed, 10 insertions(+), 10 deletions(-) > Andrew, > Could you help to pick up this minor fix? > Thanks. > Roy Any update? Thanks. Roy ___ Linuxppc-dev mailing list Linuxppc-dev@lists.ozlabs.org https://lists.ozlabs.org/listinfo/linuxppc-dev
Re: [PATCH 1/2] mmc: change ACMD12 to AUTO_CMD12 for more clear
On Wed, Aug 11, 2010 at 10:00 PM, Zang Roy-R61911 wrote: > > >> -Original Message- >> From: Zang Roy-R61911 >> Sent: Wednesday, August 11, 2010 12:47 PM >> To: Zang Roy-R61911; a...@linux-foundation.org; >> linux-...@vger.kernel.org >> Cc: linuxppc-...@ozlabs.org; mir...@gmail.com; >> cbouatmai...@gmail.com; grant.lik...@secretlab.ca >> Subject: RE: [PATCH 1/2] mmc: change ACMD12 to AUTO_CMD12 for >> more clear >> >> >> >> > -Original Message- >> > From: Zang Roy-R61911 >> > Sent: Tuesday, August 10, 2010 17:47 PM >> > To: a...@linux-foundation.org; linux-...@vger.kernel.org >> > Cc: linuxppc-...@ozlabs.org; mir...@gmail.com; >> > cbouatmai...@gmail.com; grant.lik...@secretlab.ca >> > Subject: [PATCH 1/2] mmc: change ACMD12 to AUTO_CMD12 for more clear >> > >> > Change ACMD12 to AUTO_CMD12 to reduce the confusion. >> > ACMD12 might be confused with MMC/SD App CMD 12 (CMD55+CMD12 combo). >> > >> > Signed-off-by: Roy Zang >> > --- >> > drivers/mmc/host/sdhci-of-core.c | 2 +- >> > drivers/mmc/host/sdhci.c | 8 >> > drivers/mmc/host/sdhci.h | 10 +- >> > 3 files changed, 10 insertions(+), 10 deletions(-) >> Andrew, >> Could you help to pick up this minor fix? >> Thanks. >> Roy > Any update? > Thanks. > Roy Patience Roy. You only sent the patch 1 day ago. g. ___ Linuxppc-dev mailing list Linuxppc-dev@lists.ozlabs.org https://lists.ozlabs.org/listinfo/linuxppc-dev
Query regarding 2.6.335 RT[Ingo's] and Non-RT performance
Hello All,
I created a very simple program which has higher priority than normal
tasks and runs a tight loop. Under same test environment I ran this
program on both non-rt and rt 2.6.33.5 kernel. To my suprise I see that
performance of non-RT kernel is better than RT. non-RT kernel took 3 sec and
366156 usec while RT kernel took about 3 sec and 418011 usec.Can someone
please explain why the performance of non-rt kernel is better than rt
kernel? From the face of the test result, I feel RT has more overhead,Is
there any configuration that I could do to bring down the overhead?
Processor:
processor : 0
cpu : 7448
clock : 996.00MHz
revision: 2.2 (pvr 8004 0202)
bogomips: 83.10
processor : 1
cpu : 7448
clock : 996.00MHz
revision: 2.2 (pvr 8004 0202)
bogomips: 83.10
CFS optimization:
--
# cat /proc/sys/kernel/sched_rt_runtime_us
100
# cat /proc/sys/kernel/sched_rt_period_us
100
# cat /proc/sys/kernel/sched_compat_yield
1
Test Program:
-
main()
{
int sched_rr_min,sched_rr_max;
struct sched_param scheduling_parameters;
struct timeval tv,late_tv;
suseconds_t usec_diff,avg_usec = 0;
time_t sec_diff, avg_sec = 0;
int i;
long count = 1;
sched_rr_min = sched_get_priority_min(SCHED_RR);
sched_rr_max = sched_get_priority_max(SCHED_RR);
scheduling_parameters.sched_priority = sched_rr_min+4;
sched_setscheduler(0, SCHED_RR, &scheduling_parameters);// Run the
process with the given priority
for(i = 0 ; i < 150 ; i++) {
gettimeofday(&tv, NULL);
while(count > 0){
//printf(".");
count++;
}
gettimeofday(&late_tv, NULL);
count = 1;
sec_diff = (late_tv.tv_sec - tv.tv_sec);
avg_sec += sec_diff;
usec_diff = ( (late_tv.tv_usec > tv.tv_usec) ? (late_tv.tv_usec -
tv.tv_usec) : ( tv.tv_usec - late_tv.tv_usec));
avg_usec += usec_diff;
printf("Iteration #%d sec %x usec %x\n",i,(sec_diff),(usec_diff));
}
printf("Average of #%d sec %x usec %x\n",i,(avg_sec/i),(avg_usec)/i);
}
Partial Result of non-rt kernel:
---
Iteration #140 sec 3 usec 3aef8
Iteration #141 sec 3 usec 3aefe
Iteration #142 sec 3 usec 3aee4
*Iteration #143 sec 4 usec b935b [Why there is this periodic bump ??]
[Scheduler at work??]*
Iteration #144 sec 3 usec 3aef2
Iteration #145 sec 3 usec 3aef0
Iteration #146 sec 3 usec 3aef4
*Iteration #147 sec 4 usec b934b*
Iteration #148 sec 3 usec 3aeed
Iteration #149 sec 3 usec 3aef9
Partial Result of rt kernel:
---
Iteration #135 sec 3 usec 47328
*Iteration #136 sec 4 usec ac4fd
*Iteration #137 sec 3 usec 48b0b
Iteration #138 sec 3 usec 4738c
Iteration #139 sec 4 usec ac4d5
Iteration #140 sec 3 usec 483cb
Iteration #141 sec 3 usec 48500
*Iteration #142 sec 4 usec acc49
*Iteration #143 sec 3 usec 47c1f
Iteration #144 sec 3 usec 478c2
Iteration #145 sec 3 usec 47e48
Iteration #146 sec 4 usec ac9b5
Iteration #147 sec 3 usec 48de4
Iteration #148 sec 3 usec 46fbe
Iteration #149 sec 4 usec ac52e
Average of #150 sec 3 usec 660db
Thanks,
Mani
--
Thanks,
Manik
Think twice about a tree before you take a printout
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