unsigned long tb_ticks_per_jiffy;
unsigned long tb_ticks_per_usec = 100; /* sane default */
+EXPORT_SYMBOL(tb_ticks_per_usec);
unsigned long tb_ticks_per_sec;
-unsigned long next_xtime_sync_tb;
-unsigned long xtime_sync_interval;
unsigned long tb_to_xs;
unsigned tb_to_us;
unsigned long processor_freq;
* The conversion to microseconds at the end is done
* without a divide (and in fact, without a multiply)
*/
- tb_ticks = tb_val - do_gtod.tb_orig_stamp;
temp_varp = do_gtod.varp;
+ tb_ticks = tb_val - temp_varp->tb_orig_stamp;
temp_tb_to_xs = temp_varp->tb_to_xs;
temp_stamp_xsec = temp_varp->stamp_xsec;
tb_xsec = mulhdu( tb_ticks, temp_tb_to_xs );
{
struct timeval my_tv;
- if (cur_tb > next_xtime_sync_tb) {
- next_xtime_sync_tb = cur_tb + xtime_sync_interval;
- __do_gettimeofday(&my_tv, cur_tb);
+ __do_gettimeofday(&my_tv, cur_tb);
- if (xtime.tv_sec <= my_tv.tv_sec) {
- xtime.tv_sec = my_tv.tv_sec;
- xtime.tv_nsec = my_tv.tv_usec * 1000;
- }
+ if (xtime.tv_sec <= my_tv.tv_sec) {
+ xtime.tv_sec = my_tv.tv_sec;
+ xtime.tv_nsec = my_tv.tv_usec * 1000;
}
}
+/*
+ * When the timebase - tb_orig_stamp gets too big, we do a manipulation
+ * between tb_orig_stamp and stamp_xsec. The goal here is to keep the
+ * difference tb - tb_orig_stamp small enough to always fit inside a
+ * 32 bits number. This is a requirement of our fast 32 bits userland
+ * implementation in the vdso. If we "miss" a call to this function
+ * (interrupt latency, CPU locked in a spinlock, ...) and we end up
+ * with a too big difference, then the vdso will fallback to calling
+ * the syscall
+ */
+static __inline__ void timer_recalc_offset(unsigned long cur_tb)
+{
+ struct gettimeofday_vars * temp_varp;
+ unsigned temp_idx;
+ unsigned long offset, new_stamp_xsec, new_tb_orig_stamp;
+
+ if (((cur_tb - do_gtod.varp->tb_orig_stamp) & 0x80000000u) == 0)
+ return;
+
+ temp_idx = (do_gtod.var_idx == 0);
+ temp_varp = &do_gtod.vars[temp_idx];
+
+ new_tb_orig_stamp = cur_tb;
+ offset = new_tb_orig_stamp - do_gtod.varp->tb_orig_stamp;
+ new_stamp_xsec = do_gtod.varp->stamp_xsec + mulhdu(offset, do_gtod.varp->tb_to_xs);
+
+ temp_varp->tb_to_xs = do_gtod.varp->tb_to_xs;
+ temp_varp->tb_orig_stamp = new_tb_orig_stamp;
+ temp_varp->stamp_xsec = new_stamp_xsec;
+ smp_mb();
+ do_gtod.varp = temp_varp;
+ do_gtod.var_idx = temp_idx;
+
+ ++(systemcfg->tb_update_count);
+ smp_wmb();
+ systemcfg->tb_orig_stamp = new_tb_orig_stamp;
+ systemcfg->stamp_xsec = new_stamp_xsec;
+ smp_wmb();
+ ++(systemcfg->tb_update_count);
+}
+
#ifdef CONFIG_SMP
unsigned long profile_pc(struct pt_regs *regs)
{
irq_enter();
-#ifndef CONFIG_PPC_ISERIES
profile_tick(CPU_PROFILING, regs);
-#endif
lpaca->lppaca.int_dword.fields.decr_int = 0;
if (cpu == boot_cpuid) {
write_seqlock(&xtime_lock);
tb_last_stamp = lpaca->next_jiffy_update_tb;
+ timer_recalc_offset(lpaca->next_jiffy_update_tb);
do_timer(regs);
timer_sync_xtime(lpaca->next_jiffy_update_tb);
timer_check_rtc();
}
#endif
+/* collect purr register values often, for accurate calculations */
+#if defined(CONFIG_PPC_PSERIES)
+ if (cur_cpu_spec->firmware_features & FW_FEATURE_SPLPAR) {
+ struct cpu_usage *cu = &__get_cpu_var(cpu_usage_array);
+ cu->current_tb = mfspr(SPRN_PURR);
+ }
+#endif
+
irq_exit();
return 1;
time_maxerror = NTP_PHASE_LIMIT;
time_esterror = NTP_PHASE_LIMIT;
- delta_xsec = mulhdu( (tb_last_stamp-do_gtod.tb_orig_stamp), do_gtod.varp->tb_to_xs );
+ delta_xsec = mulhdu( (tb_last_stamp-do_gtod.varp->tb_orig_stamp),
+ do_gtod.varp->tb_to_xs );
+
new_xsec = (new_nsec * XSEC_PER_SEC) / NSEC_PER_SEC;
new_xsec += new_sec * XSEC_PER_SEC;
if ( new_xsec > delta_xsec ) {
* before 1970 ... eg. we booted ten days ago, and we are setting
* the time to Jan 5, 1970 */
do_gtod.varp->stamp_xsec = new_xsec;
- do_gtod.tb_orig_stamp = tb_last_stamp;
+ do_gtod.varp->tb_orig_stamp = tb_last_stamp;
systemcfg->stamp_xsec = new_xsec;
systemcfg->tb_orig_stamp = tb_last_stamp;
}
xtime.tv_sec = mktime(tm.tm_year + 1900, tm.tm_mon + 1, tm.tm_mday,
tm.tm_hour, tm.tm_min, tm.tm_sec);
tb_last_stamp = get_tb();
- do_gtod.tb_orig_stamp = tb_last_stamp;
do_gtod.varp = &do_gtod.vars[0];
do_gtod.var_idx = 0;
+ do_gtod.varp->tb_orig_stamp = tb_last_stamp;
+ get_paca()->next_jiffy_update_tb = tb_last_stamp + tb_ticks_per_jiffy;
do_gtod.varp->stamp_xsec = xtime.tv_sec * XSEC_PER_SEC;
do_gtod.tb_ticks_per_sec = tb_ticks_per_sec;
do_gtod.varp->tb_to_xs = tb_to_xs;
systemcfg->stamp_xsec = xtime.tv_sec * XSEC_PER_SEC;
systemcfg->tb_to_xs = tb_to_xs;
- xtime_sync_interval = tb_ticks_per_sec - (tb_ticks_per_sec/8);
- next_xtime_sync_tb = tb_last_stamp + xtime_sync_interval;
-
time_freq = 0;
xtime.tv_nsec = 0;
stamp_xsec which is the time (in 1/2^20 second units) corresponding to tb_orig_stamp. This
new value of stamp_xsec compensates for the change in frequency (implied by the new tb_to_xs)
which guarantees that the current time remains the same */
- tb_ticks = get_tb() - do_gtod.tb_orig_stamp;
+ write_seqlock_irqsave( &xtime_lock, flags );
+ tb_ticks = get_tb() - do_gtod.varp->tb_orig_stamp;
div128_by_32( 1024*1024, 0, new_tb_ticks_per_sec, &divres );
new_tb_to_xs = divres.result_low;
new_xsec = mulhdu( tb_ticks, new_tb_to_xs );
- write_seqlock_irqsave( &xtime_lock, flags );
old_xsec = mulhdu( tb_ticks, do_gtod.varp->tb_to_xs );
new_stamp_xsec = do_gtod.varp->stamp_xsec + old_xsec - new_xsec;
values in do_gettimeofday. We alternate the copies and as long as a reasonable time elapses between
changes, there will never be inconsistent values. ntpd has a minimum of one minute between updates */
- if (do_gtod.var_idx == 0) {
- temp_varp = &do_gtod.vars[1];
- temp_idx = 1;
- }
- else {
- temp_varp = &do_gtod.vars[0];
- temp_idx = 0;
- }
+ temp_idx = (do_gtod.var_idx == 0);
+ temp_varp = &do_gtod.vars[temp_idx];
+
temp_varp->tb_to_xs = new_tb_to_xs;
temp_varp->stamp_xsec = new_stamp_xsec;
- mb();
+ temp_varp->tb_orig_stamp = do_gtod.varp->tb_orig_stamp;
+ smp_mb();
do_gtod.varp = temp_varp;
do_gtod.var_idx = temp_idx;
* loops back and reads them again until this criteria is met.
*/
++(systemcfg->tb_update_count);
- wmb();
+ smp_wmb();
systemcfg->tb_to_xs = new_tb_to_xs;
systemcfg->stamp_xsec = new_stamp_xsec;
- wmb();
+ smp_wmb();
++(systemcfg->tb_update_count);
write_sequnlock_irqrestore( &xtime_lock, flags );
git://git.onelab.eu / linux-2.6.git / blobdiff