On Tue, Feb 26, 2008 at 01:59:31PM +0800, Dave Young wrote:
> On Tue, Feb 26, 2008 at 1:48 PM, Dave Young <[EMAIL PROTECTED]> wrote:
> > On Tue, Feb 26, 2008 at 1:22 PM, Randy Dunlap <[EMAIL PROTECTED]> wrote:
> > > On Mon, 25 Feb 2008 10:14:36 +0800 Dave Young wrote:
> > >
> > > > On Sun, Feb 24, 2008 at 8:46 AM, Dave Jones <[EMAIL PROTECTED]> wrote:
> > > > > The boot_delay switch seems to be behaving strangely in the
> > > > > current -git. Setting it to =10 makes the output 'bursty'
> > > > > it becomes slow for some printk's whilst others scroll by
> > > > > at regular speed.
> > > > > Setting it any higher than that seems to make it pause for
> > > > > a really long time before it outputs any text at all.
> > > >
> > > > On my side there's this issue for a long time
> > > > http://lkml.org/lkml/2007/8/8/79
> > >
> > > [http://marc.info/?l=linux-kernel&m=118655896515049&w=2]
> > >
> > > You asked questions and they were answered. Perhaps you didn't like
> > > the answers.
> >
> > No, I like it. Thanks.
> >
> > But I still want to know why mdelay can not be used.
> > is it not available for all archs or something else?
> >
> >
> > >
> > > Here's a question for you. What kernel boot options did you use?
> > > Specifically, for lpj= and boot_delay= ?
> >
> > I tried boot_delay=100 and boot_delay=200 without lpj set, The result
> > was really slow. It was better with lpj copied from dmesg, but was
> > still slower then mdelay.
>
> Especially at the very beginning after the message "Booting the kernel",
> I need to wait several minutes to see the afterwards messages
>
> >
> > I think we can firstly use preset lpj, after delay calibrating just
> > use the system lpj
> >
> >
> >
> > >
> > > > >
> > > > > x86 timer changes perhaps ?
> > >
> > >
> > > ---
> > > ~Randy
> > >
> >
How about use loops_per_jiffy as following? With this patch at least
for me the very long delay at the very begining does not occur.
kernel/printk.c | 15 ++++-----------
1 file changed, 4 insertions(+), 11 deletions(-)
diff -upr linux/kernel/printk.c linux.new/kernel/printk.c
--- linux/kernel/printk.c 2008-02-26 16:54:23.000000000 +0800
+++ linux.new/kernel/printk.c 2008-02-26 16:59:02.000000000 +0800
@@ -173,24 +173,14 @@ __setup("log_buf_len=", log_buf_len_setu
#ifdef CONFIG_BOOT_PRINTK_DELAY
static unsigned int boot_delay; /* msecs delay after each printk during bootup
*/
-static unsigned long long printk_delay_msec; /* per msec, based on boot_delay
*/
static int __init boot_delay_setup(char *str)
{
- unsigned long lpj;
- unsigned long long loops_per_msec;
-
- lpj = preset_lpj ? preset_lpj : 1000000; /* some guess */
- loops_per_msec = (unsigned long long)lpj / 1000 * HZ;
-
get_option(&str, &boot_delay);
if (boot_delay > 10 * 1000)
boot_delay = 0;
- printk_delay_msec = loops_per_msec;
- printk(KERN_DEBUG "boot_delay: %u, preset_lpj: %ld, lpj: %lu, "
- "HZ: %d, printk_delay_msec: %llu\n",
- boot_delay, preset_lpj, lpj, HZ, printk_delay_msec);
+ printk(KERN_DEBUG "boot_delay: %u\n", boot_delay);
return 1;
}
__setup("boot_delay=", boot_delay_setup);
@@ -199,6 +189,9 @@ static void boot_delay_msec(void)
{
unsigned long long k;
unsigned long timeout;
+ unsigned long long printk_delay_msec;
+
+ printk_delay_msec = (unsigned long long)loops_per_jiffy / 1000 * HZ;
if (boot_delay == 0 || system_state != SYSTEM_BOOTING)
return;
--
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