Hi Erik,
After making the following changes in kernel/Kconfig.hz and again after
rebuilding and booting from this
newly configured kernel, i still get the same HZ value.
<snip>
#
# Timer Interrupt Frequency Configuration
#
choice
prompt "Timer frequency"
default HZ_10000 <====
----
----
config HZ
int
default 100 if HZ_100
default 250 if HZ_250
default 300 if HZ_300
default 1000 if HZ_1000
default 10000 if HZ_10000
<snip>
Though the customer is having 2.4 kernel,but i was giving a try on
2.6first(because the building
procedure failed,seems to be due to a higher version of gcc, and as i didn't
had
and i just checked that the same file ,i.e. kernel/Kconfig.hz is not
available for 2.4
~amit
On Jan 10, 2008 3:02 PM, Erik Mouw <[EMAIL PROTECTED]> wrote:
> On Thu, Jan 10, 2008 at 02:31:46PM +0530, amit mehta wrote:
> > One of our customer is facing an issue with jiffies wrap up.
> > on a 32 bit machine, the variable jiffies count upto 472 days.
> > the customer's server was up for 472 days ('uptime') and to reproduce
> > the same, i tried to tweak with the variable HZ in
> > linux-2.6..23.9/include/asm-i386/param.h
> > but it seems that it is not working(i may be doing something stupid as
> well)
>
> Problems with jiffies wrapup shouldn't happen with 2.6 kernels anymore
> because jiffies is initialised at a couple of minutes before wrap up.
> That shook out quite some jiffies wrap up bugs.
>
> > i changed HZ from 100 to 10000 in
> linux-2.6..23.9/include/asm-i386/param.h .
>
> Better do it in kernel/Kconfig.hz
>
> > Then after rebuilding the kernel.and booting from it
> > i inserted a small module to read the jiffies and HZ global variable( i
> > don't know if there is any user level command to read the same) ,which
> is as
> > follows:
> >
> > [EMAIL PROTECTED] drivers]# cat get_jiffies.c
> > #include <linux/init.h>
> > #include <linux/module.h>
> > #include <asm/current.h>
> > #include <linux/sched.h>
> > #include <linux/time.h>
> > #include <linux/jiffies.h>
> > static int __init jiffies_init(void)
> > {
> > unsigned long j,z;
> > j = z = 0;
> > j = jiffies;
> > z = HZ;
> > printk(KERN_ALERT "jiffies value is %lu\n",j);
> > printk(KERN_ALERT "jiffies value in seconds %lu\n",(jiffies/HZ));
> > printk(KERN_ALERT "HZ value is %lu\n",z);
> > return 0;
> > }
> >
> > static void __exit jiffies_exit(void)
> > {
> > printk(KERN_ALERT "Goodbye, world!\n");
> > }
> >
> > module_init(jiffies_init);
> > module_exit(jiffies_exit);
> >
> > MODULE_LICENSE("GPL");
> >
> > [EMAIL PROTECTED] drivers]# insmod get_jiffies.ko
> > [EMAIL PROTECTED] drivers]# dmesg
> > jiffies value is 372939
> > jiffies value in seconds 1491
> > HZ value is 250 <====
> >
> > why this HZ variable is shown as 250 ?
>
> Because it is overridden from kernel/Kconfig.hz .
>
>
> Erik
>
> --
> They're all fools. Don't worry. Darwin may be slow, but he'll
> eventually get them. -- Matthew Lammers in alt.sysadmin.recovery
>
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