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.
x86 timer changes perhaps ?
Dave
--
http://www.codemonkey.org.uk
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
>
> x86 timer changes perhaps ?
>
> Dave
>
> --
> http://www.codemonkey.org.uk
> --
> To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
> the body of a message to [email protected]
> More majordomo info at http://vger.kernel.org/majordomo-info.html
> Please read the FAQ at http://www.tux.org/lkml/
>
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.
Here's a question for you. What kernel boot options did you use?
Specifically, for lpj= and boot_delay= ?
> >
> > x86 timer changes perhaps ?
---
~Randy
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.
I think we can firstly use preset lpj, after delay calibrating just
use the system lpj
>
> > >
> > > x86 timer changes perhaps ?
>
>
> ---
> ~Randy
>
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
> >
>
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;
On Tue, 26 Feb 2008 17:09:48 +0800 Dave Young wrote:
> 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;
> --
Hi Dave,
That might work, but IMO it requires someone to audit all
architectures to make sure that loops_per_jiffy has been calibrated
at that point in time (as I mentioned in http://lkml.org/lkml/2007/8/11/153).
I didn't do that and you said that you tested i386 only.
Maybe you can get Andrew to merge it into -mm for testing...
However, setting boot_delay=N without setting lpj=M is just not
advisable. The Kconfig help text for BOOT_PRINTK_DELAY tries to
say that. Maybe it needs to be stronger?
It is likely that you would also need to use "lpj=M" to preset
the "loops per jiffie" value.
See a previous boot log for the "lpj" value to use for your
system, and then set "lpj=M" before setting "boot_delay=N".
---
~Randy
On Wed, Feb 27, 2008 at 1:33 AM, Randy Dunlap <[email protected]> wrote:
>
> On Tue, 26 Feb 2008 17:09:48 +0800 Dave Young wrote:
>
> > 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;
> > --
>
> Hi Dave,
>
> That might work, but IMO it requires someone to audit all
> architectures to make sure that loops_per_jiffy has been calibrated
> at that point in time
>(as I mentioned in http://lkml.org/lkml/2007/8/11/153).
Sorry for missing your words about this.
>
> I didn't do that and you said that you tested i386 only.
>
> Maybe you can get Andrew to merge it into -mm for testing...
Andrew, what's your opinon?
>
> However, setting boot_delay=N without setting lpj=M is just not
> advisable. The Kconfig help text for BOOT_PRINTK_DELAY tries to
> say that. Maybe it needs to be stronger?
I think it's enough now.
I tested boot_delay yestoday, and found the result is different with
before version.
Even with lpj preset the delay is very slow, 5-10 seconds for every printk.
Maybe this is what davej said.
I will do some more test and hack about this today.
>
> It is likely that you would also need to use "lpj=M" to preset
> the "loops per jiffie" value.
> See a previous boot log for the "lpj" value to use for your
> system, and then set "lpj=M" before setting "boot_delay=N".
>
>
> ---
> ~Randy
>
On Sat 2008-02-23 19:46:15, Dave Jones 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.
>
> x86 timer changes perhaps ?
If nohz=off highres=off notsc fixes it, it is probably timers :-).
--
(english) http://www.livejournal.com/~pavelmachek
(cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html
On Wed, Feb 27, 2008 at 10:01 AM, Dave Young <[email protected]> wrote:
>
> On Wed, Feb 27, 2008 at 1:33 AM, Randy Dunlap <[email protected]> wrote:
> >
> > On Tue, 26 Feb 2008 17:09:48 +0800 Dave Young wrote:
> >
> > > 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
Answer to myself : It's due to the first delayed printk.
> > > >
> > > > >
> > > > > 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.
It does impoving the code, but does not resolve problem here.
It looks ok because the loops_per_jiffy initial value is 4096, with
this value the delay result is much better than with values copied
from calibrated results.
BTW, Pavel's suggest (nohz=off highres=off notsc) does not help me.
> > >
> > > 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;
> > > --
> >
> > Hi Dave,
> >
> > That might work, but IMO it requires someone to audit all
> > architectures to make sure that loops_per_jiffy has been calibrated
> > at that point in time
> >(as I mentioned in http://lkml.org/lkml/2007/8/11/153).
>
> Sorry for missing your words about this.
>
>
> >
> > I didn't do that and you said that you tested i386 only.
> >
> > Maybe you can get Andrew to merge it into -mm for testing...
>
> Andrew, what's your opinon?
>
>
> >
> > However, setting boot_delay=N without setting lpj=M is just not
> > advisable. The Kconfig help text for BOOT_PRINTK_DELAY tries to
> > say that. Maybe it needs to be stronger?
>
> I think it's enough now.
>
> I tested boot_delay yestoday, and found the result is different with
> before version.
> Even with lpj preset the delay is very slow, 5-10 seconds for every printk.
> Maybe this is what davej said.
>
> I will do some more test and hack about this today.
>
>
>
> >
> > It is likely that you would also need to use "lpj=M" to preset
> > the "loops per jiffie" value.
> > See a previous boot log for the "lpj" value to use for your
> > system, and then set "lpj=M" before setting "boot_delay=N".
> >
> >
> > ---
> > ~Randy
> >
>