On Thu, 2005-08-04 at 14:59 +0200, Borislav Petkov wrote: > Hi, > > on my laptop ASUS M6B00N PRINTK_TIME is enabled in order to show timing > information in all the boottime printk's. However, all output looks like this > > <snip> > [4294667.997000] CPU: After generic identify, caps: a7e9fbbf 00000000 > 00000000 > 00000000 00000180 00000000 00000000 > [4294667.997000] CPU: After vendor identify, caps: a7e9fbbf 00000000 00000000 > 00000000 00000180 00000000 00000000 > [4294667.997000] CPU: L1 I cache: 32K, L1 D cache: 32K > [4294667.997000] CPU: L2 cache: 1024K > [4294667.997000] CPU: After all inits, caps: a7e9fbbf 00000000 00000000 > 00000040 00000180 00000000 00000000 > [4294667.997000] CPU: Intel(R) Pentium(R) M processor 1500MHz stepping 05 > [4294667.997000] Enabling fast FPU save and restore... done. > [4294667.997000] Enabling unmasked SIMD FPU exception support... done. > [4294667.997000] Checking 'hlt' instruction... OK. > [4294668.041000] ACPI: setting ELCR to 0200 (from 0c30) > </snip> > > If I'm not wrong, the time value that gets printed is actually the jiffies_64 > value set to INITIAL_JIFFIES, which in turn is set to wrap 5 minutes after > boot so that "jiffies wrap bugs show up earlier." This is because > sched_clock() in <arch/i386/kernel/timers/timer_tsc.c> returns the jiffies_64 > value converted to nanoseconds after checking use_tsc. This, in turn, is 0 > because my machine selects the power management timer as the high-res > timesource before reading the timestamp counter for printk timing. > [snip] > After applying it, printk timing looks like this: > > <snip> > [ 0.000000] Detected 1500.132 MHz processor. > [ 0.000000] Using pmtmr for high-res timesource > [ 0.000000] Console: colour VGA+ 80x25 > [ 1.890000] Dentry cache hash table entries: 131072 (order: 7, 524288 > bytes) > [ 1.891000] Inode-cache hash table entries: 65536 (order: 6, 262144 bytes) > [ 1.906000] Memory: 513756k/523520k available (2839k kernel code, 9276k > reserved, 1148k data, 152k init, 0k highmem) > [ 1.906000] Checking if this processor honours the WP bit even in > supervisor mode... Ok. > [ 1.906000] Calibrating delay loop... 2973.69 BogoMIPS (lpj=1486848) > [ 1.928000] Security Framework v1.0.0 initialized > </snip> > > > Signed-off-by: Borislav Petkov <[EMAIL PROTECTED]> > > --- arch/i386/kernel/timers/timer_tsc.c.orig 2005-08-04 12:57:37.000000000 > +0200 > +++ arch/i386/kernel/timers/timer_tsc.c 2005-08-04 14:19:48.000000000 > +0200 > @@ -146,7 +146,7 @@ unsigned long long sched_clock(void) > if (!use_tsc) > #endif > /* no locking but a rare wrong value is not a big deal */ > - return jiffies_64 * (1000000000 / HZ); > + return (jiffies_64 - INITIAL_JIFFIES) * (1000000000 / HZ); > > /* Read the Time Stamp Counter */ > rdtscll(this_offset); > >
This patch looks fine to me. -john - 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/
