[PATCH][RESEND] linux-2.5.58_timer-tsc-cleanup_A0

[PATCH][RESEND] linux-2.5.58_timer-tsc-cleanup_A0

[john stultz]

Linus, All,
	This patch cleans up the timer_tsc code, removing the unused use_tsc
variable and making fast_gettimeoffset_quotient static.

Please apply.

thanks
-john


diff -Nru a/arch/i386/kernel/smpboot.c b/arch/i386/kernel/smpboot.c
--- a/arch/i386/kernel/smpboot.c	Wed Jan 15 15:54:11 2003
+++ b/arch/i386/kernel/smpboot.c	Wed Jan 15 15:54:11 2003
@@ -182,8 +182,6 @@
 
 #define NR_LOOPS 5
 
-extern unsigned long fast_gettimeoffset_quotient;
-
 /*
  * accurate 64-bit/32-bit division, expanded to 32-bit divisions and 64-bit
  * multiplication. Not terribly optimized but we need it at boot time only
@@ -223,7 +221,8 @@
 
 	printk("checking TSC synchronization across %u CPUs: ", num_booting_cpus());
 
-	one_usec = ((1<<30)/fast_gettimeoffset_quotient)*(1<<2);
+	/* convert from kcyc/sec to cyc/usec */
+	one_usec = cpu_khz / 1000;
 
 	atomic_set(&tsc_start_flag, 1);
 	wmb();
diff -Nru a/arch/i386/kernel/timers/timer_tsc.c b/arch/i386/kernel/timers/timer_tsc.c
--- a/arch/i386/kernel/timers/timer_tsc.c	Wed Jan 15 15:54:11 2003
+++ b/arch/i386/kernel/timers/timer_tsc.c	Wed Jan 15 15:54:11 2003
@@ -18,7 +18,6 @@
 
 extern spinlock_t i8253_lock;
 
-static int use_tsc;
 /* Number of usecs that the last interrupt was delayed */
 static int delay_at_last_interrupt;
 
@@ -29,7 +28,7 @@
  * Equal to 2^32 * (1 / (clocks per usec) ).
  * Initialized in time_init.
  */
-unsigned long fast_gettimeoffset_quotient;
+static unsigned long fast_gettimeoffset_quotient;
 
 static unsigned long get_offset_tsc(void)
 {
@@ -277,7 +276,6 @@
 		unsigned long tsc_quotient = calibrate_tsc();
 		if (tsc_quotient) {
 			fast_gettimeoffset_quotient = tsc_quotient;
-			use_tsc = 1;
 			/*
 			 *	We could be more selective here I suspect
 			 *	and just enable this for the next intel chips ?

Re: [PATCH][RESEND] linux-2.5.58_timer-tsc-cleanup_A0

[Rusty Russell]

In message <1042676113.1515.129.camel@w-jstultz2.beaverton.ibm.com> you write:
> Linus, All,
> 	This patch cleans up the timer_tsc code, removing the unused use_tsc
> variable and making fast_gettimeoffset_quotient static.

But use_tsc is still used:

static int
time_cpufreq_notifier(struct notifier_block *nb, unsigned long val,
		       void *data)
{

....

#ifndef CONFIG_SMP
		if (use_tsc) {
			fast_gettimeoffset_quotient = cpufreq_scale(fast_gettimeoffset_ref, freq->new, ref_freq);
			cpu_khz = cpufreq_scale(cpu_khz_ref, ref_freq, freq->new);
		}
#endif


And almost any patch to the x86 boot code is too convoluted to be
"trivial" IMHO.

Sorry,
Rusty.
--
  Anyone who quotes me in their sig is an idiot. -- Rusty Russell.

Re: [PATCH][RESEND] linux-2.5.58_timer-tsc-cleanup_A0

[john stultz]

On Fri, 2003-01-17 at 17:48, Rusty Russell wrote:
> In message <1042676113.1515.129.camel@w-jstultz2.beaverton.ibm.com> you write:
> > Linus, All,
> > 	This patch cleans up the timer_tsc code, removing the unused use_tsc
> > variable and making fast_gettimeoffset_quotient static.
> 
> But use_tsc is still used:

Yep, this was pointed out earlier today. My bad. The cpu_freq updates
that went in a tad bit less then 2 weeks ago slipped it in and I just
didn't notice. I apologize. Thanks for looking at it, though. 

> 
> And almost any patch to the x86 boot code is too convoluted to be
> "trivial" IMHO.

Ok, sounds fair.

Thanks
-john