[PATCH 3/3] Remove time-interpolators

From: Guennadi Liakhovetski
Date: Thu Oct 19 2006 - 11:20:49 EST

Remove CONFIG_TIME_INTERPOLATION - never set either.

Thanks
Guennadi
---------------------------------
Guennadi Liakhovetski, Ph.D.
DSA Daten- und Systemtechnik GmbH
Pascalstr. 28
D-52076 Aachen
Germany

Signed-off-by: G. Liakhovetski <gl@xxxxxxxxx>

diff --exclude=CVS -ur linux-2.6.18-rt6/arch/ia64/kernel/asm-offsets.c linux-2.6.18-rt6-rmdead/arch/ia64/kernel/asm-offsets.c
--- linux-2.6.18-rt6/arch/ia64/kernel/asm-offsets.c 2006-10-19 15:52:47.662033868 +0200
+++ linux-2.6.18-rt6-rmdead/arch/ia64/kernel/asm-offsets.c 2006-10-19 15:57:26.945526349 +0200
@@ -254,14 +254,4 @@
DEFINE(IA64_PMSA_XIP_OFFSET,
offsetof (struct pal_min_state_area_s, pmsa_xip));
BLANK();
-
-#ifdef CONFIG_TIME_INTERPOLATION
- /* used by fsys_gettimeofday in arch/ia64/kernel/fsys.S */
- DEFINE(IA64_TIMESPEC_TV_NSEC_OFFSET, offsetof (struct timespec, tv_nsec));
- DEFINE(IA64_CLOCKSOURCE_MASK_OFFSET, offsetof (struct clocksource, mask));
- DEFINE(IA64_CLOCKSOURCE_MULT_OFFSET, offsetof (struct clocksource, mult));
- DEFINE(IA64_CLOCKSOURCE_SHIFT_OFFSET, offsetof (struct clocksource, shift));
- DEFINE(IA64_CLOCKSOURCE_MMIO_PTR_OFFSET, offsetof (struct clocksource, fsys_mmio_ptr));
- DEFINE(IA64_CLOCKSOURCE_CYCLE_LAST_OFFSET, offsetof (struct clocksource, cycle_last));
-#endif
}
diff --exclude=CVS -ur linux-2.6.18-rt6/arch/ia64/kernel/fsys.S linux-2.6.18-rt6-rmdead/arch/ia64/kernel/fsys.S
--- linux-2.6.18-rt6/arch/ia64/kernel/fsys.S 2006-10-19 15:52:47.664033434 +0200
+++ linux-2.6.18-rt6-rmdead/arch/ia64/kernel/fsys.S 2006-10-19 15:59:09.069399735 +0200
@@ -24,319 +24,6 @@

#include "entry.h"

-#ifdef CONFIG_TIME_INTERPOLATION
-/*
- * See Documentation/ia64/fsys.txt for details on fsyscalls.
- *
- * On entry to an fsyscall handler:
- * r10 = 0 (i.e., defaults to "successful syscall return")
- * r11 = saved ar.pfs (a user-level value)
- * r15 = system call number
- * r16 = "current" task pointer (in normal kernel-mode, this is in r13)
- * r32-r39 = system call arguments
- * b6 = return address (a user-level value)
- * ar.pfs = previous frame-state (a user-level value)
- * PSR.be = cleared to zero (i.e., little-endian byte order is in effect)
- * all other registers may contain values passed in from user-mode
- *
- * On return from an fsyscall handler:
- * r11 = saved ar.pfs (as passed into the fsyscall handler)
- * r15 = system call number (as passed into the fsyscall handler)
- * r32-r39 = system call arguments (as passed into the fsyscall handler)
- * b6 = return address (as passed into the fsyscall handler)
- * ar.pfs = previous frame-state (as passed into the fsyscall handler)
- */
-
-ENTRY(fsys_ni_syscall)
- .prologue
- .altrp b6
- .body
- mov r8=ENOSYS
- mov r10=-1
- FSYS_RETURN
-END(fsys_ni_syscall)
-
-ENTRY(fsys_getpid)
- .prologue
- .altrp b6
- .body
- add r9=TI_FLAGS+IA64_TASK_SIZE,r16
- ;;
- ld4 r9=[r9]
- add r8=IA64_TASK_TGID_OFFSET,r16
- ;;
- and r9=TIF_ALLWORK_MASK,r9
- ld4 r8=[r8] // r8 = current->tgid
- ;;
- cmp.ne p8,p0=0,r9
-(p8) br.spnt.many fsys_fallback_syscall
- FSYS_RETURN
-END(fsys_getpid)
-
-ENTRY(fsys_getppid)
- .prologue
- .altrp b6
- .body
- add r17=IA64_TASK_GROUP_LEADER_OFFSET,r16
- ;;
- ld8 r17=[r17] // r17 = current->group_leader
- add r9=TI_FLAGS+IA64_TASK_SIZE,r16
- ;;
-
- ld4 r9=[r9]
- add r17=IA64_TASK_REAL_PARENT_OFFSET,r17 // r17 = &current->group_leader->real_parent
- ;;
- and r9=TIF_ALLWORK_MASK,r9
-
-1: ld8 r18=[r17] // r18 = current->group_leader->real_parent
- ;;
- cmp.ne p8,p0=0,r9
- add r8=IA64_TASK_TGID_OFFSET,r18 // r8 = &current->group_leader->real_parent->tgid
- ;;
-
- /*
- * The .acq is needed to ensure that the read of tgid has returned its data before
- * we re-check "real_parent".
- */
- ld4.acq r8=[r8] // r8 = current->group_leader->real_parent->tgid
-#ifdef CONFIG_SMP
- /*
- * Re-read current->group_leader->real_parent.
- */
- ld8 r19=[r17] // r19 = current->group_leader->real_parent
-(p8) br.spnt.many fsys_fallback_syscall
- ;;
- cmp.ne p6,p0=r18,r19 // did real_parent change?
- mov r19=0 // i must not leak kernel bits...
-(p6) br.cond.spnt.few 1b // yes -> redo the read of tgid and the check
- ;;
- mov r17=0 // i must not leak kernel bits...
- mov r18=0 // i must not leak kernel bits...
-#else
- mov r17=0 // i must not leak kernel bits...
- mov r18=0 // i must not leak kernel bits...
- mov r19=0 // i must not leak kernel bits...
-#endif
- FSYS_RETURN
-END(fsys_getppid)
-
-ENTRY(fsys_set_tid_address)
- .prologue
- .altrp b6
- .body
- add r9=TI_FLAGS+IA64_TASK_SIZE,r16
- ;;
- ld4 r9=[r9]
- tnat.z p6,p7=r32 // check argument register for being NaT
- ;;
- and r9=TIF_ALLWORK_MASK,r9
- add r8=IA64_TASK_PID_OFFSET,r16
- add r18=IA64_TASK_CLEAR_CHILD_TID_OFFSET,r16
- ;;
- ld4 r8=[r8]
- cmp.ne p8,p0=0,r9
- mov r17=-1
- ;;
-(p6) st8 [r18]=r32
-(p7) st8 [r18]=r17
-(p8) br.spnt.many fsys_fallback_syscall
- ;;
- mov r17=0 // i must not leak kernel bits...
- mov r18=0 // i must not leak kernel bits...
- FSYS_RETURN
-END(fsys_set_tid_address)
-
-#define CLOCK_REALTIME 0
-#define CLOCK_MONOTONIC 1
-#define CLOCK_DIVIDE_BY_1000 0x4000
-#define CLOCK_ADD_MONOTONIC 0x8000
-
-ENTRY(fsys_gettimeofday)
- .prologue
- .altrp b6
- .body
- mov r31 = r32
- tnat.nz p6,p0 = r33 // guard against NaT argument
-(p6) br.cond.spnt.few .fail_einval
- mov r30 = CLOCK_DIVIDE_BY_1000
- ;;
-.gettime:
- // Register map
- // Incoming r31 = pointer to address where to place result
- // r30 = flags determining how time is processed
- // r2,r3 = temp r4-r7 preserved
- // r8 = result nanoseconds
- // r9 = result seconds
- // r10 = temporary storage for clock difference
- // r11 = preserved: saved ar.pfs
- // r12 = preserved: memory stack
- // r13 = preserved: thread pointer
- // r14 = address of mask / mask value
- // r15 = preserved: system call number
- // r16 = preserved: current task pointer
- // r17 = wall to monotonic use
- // r19 = address of itc_lastcycle
- // r20 = struct clocksource / address of first element
- // r21 = shift value
- // r22 = address of itc_jitter/ wall_to_monotonic
- // r23 = address of shift
- // r24 = address mult factor / cycle_last value
- // r25 = itc_lastcycle value
- // r26 = address clocksource cycle_last
- // r27 = pointer to xtime
- // r28 = sequence number at the beginning of critcal section
- // r29 = address of seqlock
- // r30 = time processing flags / memory address
- // r31 = pointer to result
- // Predicates
- // p6,p7 short term use
- // p8 = timesource ar.itc
- // p9 = timesource mmio64
- // p10 = timesource mmio32 - not used
- // p11 = timesource not to be handled by asm code
- // p12 = memory time source ( = p9 | p10) - not used
- // p13 = do cmpxchg with time_interpolator_last_cycle
- // p14 = Divide by 1000
- // p15 = Add monotonic
- //
- // Note that instructions are optimized for McKinley. McKinley can process two
- // bundles simultaneously and therefore we continuously try to feed the CPU
- // two bundles and then a stop.
- tnat.nz p6,p0 = r31 // branch deferred since it does not fit into bundle structure
- mov pr = r30,0xc000 // Set predicates according to function
- add r2 = TI_FLAGS+IA64_TASK_SIZE,r16
- movl r20 = fsyscall_clock // load fsyscall clocksource address
- ;;
- add r10 = IA64_CLOCKSOURCE_MMIO_PTR_OFFSET,r20
- movl r29 = xtime_lock
- ld4 r2 = [r2] // process work pending flags
- movl r27 = xtime
- ;; // only one bundle here
- add r14 = IA64_CLOCKSOURCE_MASK_OFFSET,r20
- movl r22 = itc_jitter
- add r24 = IA64_CLOCKSOURCE_MULT_OFFSET,r20
- and r2 = TIF_ALLWORK_MASK,r2
-(p6) br.cond.spnt.few .fail_einval // deferred branch
- ;;
- ld8 r30 = [r10] // clocksource->mmio_ptr
- movl r19 = itc_lastcycle
- add r23 = IA64_CLOCKSOURCE_SHIFT_OFFSET,r20
- cmp.ne p6, p0 = 0, r2 // Fallback if work is scheduled
-(p6) br.cond.spnt.many fsys_fallback_syscall
- ;;
- ld8 r14 = [r14] // clocksource mask value
- ld4 r2 = [r22] // itc_jitter value
- add r26 = IA64_CLOCKSOURCE_CYCLE_LAST_OFFSET,r20 // clock fsyscall_cycle_last
- ld4 r3 = [r24] // clocksource->mult value
- cmp.eq p8,p9 = 0,r30 // Check for cpu timer, no mmio_ptr, set p8, clear p9
- ;;
- setf.sig f7 = r3 // Setup for mult scaling of counter
-(p15) movl r22 = wall_to_monotonic
- ld4 r21 = [r23] // shift value
-(p8) cmp.ne p13,p0 = r2,r0 // need jitter compensation, set p13
-(p9) cmp.eq p13,p0 = 0,r30 // if mmio_ptr, clear p13 jitter control
- ;;
-.time_redo:
- .pred.rel.mutex p8,p9,p10
- ld4.acq r28 = [r29] // xtime_lock.sequence. Must come first for locking purposes
-(p8) mov r2 = ar.itc // CPU_TIMER. 36 clocks latency!!!
-(p9) ld8 r2 = [r30] // readq(ti->address). Could also have latency issues..
-(p13) ld8 r25 = [r19] // get itc_lastcycle value
- ;; // could be removed by moving the last add upward
- ld8 r9 = [r27],IA64_TIMESPEC_TV_NSEC_OFFSET
- ld8 r24 = [r26] // get fsyscall_cycle_last value
-(p15) ld8 r17 = [r22],IA64_TIMESPEC_TV_NSEC_OFFSET
- ;;
- ld8 r8 = [r27],-IA64_TIMESPEC_TV_NSEC_OFFSET // xtime.tv_nsec
-(p13) sub r3 = r25,r2 // Diff needed before comparison (thanks davidm)
- ;;
-(p13) cmp.gt.unc p6,p7 = r3,r0 // check if it is less than last. p6,p7 cleared
- sub r10 = r2,r24 // current_counter - last_counter
- ;;
-(p6) sub r10 = r25,r24 // time we got was less than last_cycle
-(p7) mov ar.ccv = r25 // more than last_cycle. Prep for cmpxchg
- ;;
- and r10 = r10,r14 // Apply mask
- ;;
- setf.sig f8 = r10
- nop.i 123
- ;;
-(p7) cmpxchg8.rel r3 = [r19],r2,ar.ccv
-EX(.fail_efault, probe.w.fault r31, 3) // This takes 5 cycles and we have spare time
- xmpy.l f8 = f8,f7 // nsec_per_cyc*(counter-last_counter)
-(p15) add r9 = r9,r17 // Add wall to monotonic.secs to result secs
- ;;
-(p15) ld8 r17 = [r22],-IA64_TIMESPEC_TV_NSEC_OFFSET
-(p7) cmp.ne p7,p0 = r25,r3 // if cmpxchg not successful redo
- // simulate tbit.nz.or p7,p0 = r28,0
- and r28 = ~1,r28 // Make sequence even to force retry if odd
- getf.sig r2 = f8
- mf
- ;;
- ld4 r10 = [r29] // xtime_lock.sequence
-(p15) add r8 = r8, r17 // Add monotonic.nsecs to nsecs
- shr.u r2 = r2,r21 // shift by factor
- ;; // overloaded 3 bundles!
- // End critical section.
- add r8 = r8,r2 // Add xtime.nsecs
- cmp4.ne.or p7,p0 = r28,r10
-(p7) br.cond.dpnt.few .time_redo // sequence number changed ?
- // Now r8=tv->tv_nsec and r9=tv->tv_sec
- mov r10 = r0
- movl r2 = 1000000000
- add r23 = IA64_TIMESPEC_TV_NSEC_OFFSET, r31
-(p14) movl r3 = 2361183241434822607 // Prep for / 1000 hack
- ;;
-.time_normalize:
- mov r21 = r8
- cmp.ge p6,p0 = r8,r2
-(p14) shr.u r20 = r8, 3 // We can repeat this if necessary just wasting some time
- ;;
-(p14) setf.sig f8 = r20
-(p6) sub r8 = r8,r2
-(p6) add r9 = 1,r9 // two nops before the branch.
-(p14) setf.sig f7 = r3 // Chances for repeats are 1 in 10000 for gettod
-(p6) br.cond.dpnt.few .time_normalize
- ;;
- // Divided by 8 though shift. Now divide by 125
- // The compiler was able to do that with a multiply
- // and a shift and we do the same
-EX(.fail_efault, probe.w.fault r23, 3) // This also costs 5 cycles
-(p14) xmpy.hu f8 = f8, f7 // xmpy has 5 cycles latency so use it...
- ;;
- mov r8 = r0
-(p14) getf.sig r2 = f8
- ;;
-(p14) shr.u r21 = r2, 4
- ;;
-EX(.fail_efault, st8 [r31] = r9)
-EX(.fail_efault, st8 [r23] = r21)
- FSYS_RETURN
-.fail_einval:
- mov r8 = EINVAL
- mov r10 = -1
- FSYS_RETURN
-.fail_efault:
- mov r8 = EFAULT
- mov r10 = -1
- FSYS_RETURN
-END(fsys_gettimeofday)
-
-ENTRY(fsys_clock_gettime)
- .prologue
- .altrp b6
- .body
- cmp4.ltu p6, p0 = CLOCK_MONOTONIC, r32
- // Fallback if this is not CLOCK_REALTIME or CLOCK_MONOTONIC
-(p6) br.spnt.few fsys_fallback_syscall
- mov r31 = r33
- shl r30 = r32,15
- br.many .gettime
-END(fsys_clock_gettime)
-
-
-#else // !CONFIG_TIME_INTERPOLATION
-
# define fsys_gettimeofday 0
# define fsys_clock_gettime 0

@@ -350,9 +37,6 @@
mov r10 = -1
FSYS_RETURN

-#endif
-
-

/*
* long fsys_rt_sigprocmask (int how, sigset_t *set, sigset_t *oset, size_t sigsetsize).
diff --exclude=CVS -ur linux-2.6.18-rt6/arch/ia64/kernel/time.c linux-2.6.18-rt6-rmdead/arch/ia64/kernel/time.c
--- linux-2.6.18-rt6/arch/ia64/kernel/time.c 2006-10-19 15:52:47.675031052 +0200
+++ linux-2.6.18-rt6-rmdead/arch/ia64/kernel/time.c 2006-10-19 15:59:33.462114604 +0200
@@ -235,24 +235,6 @@
local_cpu_data->nsec_per_cyc = ((NSEC_PER_SEC<<IA64_NSEC_PER_CYC_SHIFT)
+ itc_freq/2)/itc_freq;

-#ifdef CONFIG_TIME_INTERPOLATION
- if (!(sal_platform_features & IA64_SAL_PLATFORM_FEATURE_ITC_DRIFT)) {
-#ifdef CONFIG_SMP
- /* On IA64 in an SMP configuration ITCs are never accurately synchronized.
- * Jitter compensation requires a cmpxchg which may limit
- * the scalability of the syscalls for retrieving time.
- * The ITC synchronization is usually successful to within a few
- * ITC ticks but this is not a sure thing. If you need to improve
- * timer performance in SMP situations then boot the kernel with the
- * "nojitter" option. However, doing so may result in time fluctuating (maybe
- * even going backward) if the ITC offsets between the individual CPUs
- * are too large.
- */
- if (!nojitter) itc_jitter = 1;
-#endif
- }
-#endif
-
/* Setup the CPU local timer tick */
ia64_cpu_local_tick();

diff --exclude=CVS -ur linux-2.6.18-rt6/include/linux/timex.h linux-2.6.18-rt6-rmdead/include/linux/timex.h
--- linux-2.6.18-rt6/include/linux/timex.h 2006-10-19 15:52:47.893983617 +0200
+++ linux-2.6.18-rt6-rmdead/include/linux/timex.h 2006-10-19 16:05:14.451270841 +0200
@@ -224,66 +224,6 @@
__x < 0 ? -(-__x >> __s) : __x >> __s; \
})

-
-#ifdef CONFIG_TIME_INTERPOLATION
-
-#define TIME_SOURCE_CPU 0
-#define TIME_SOURCE_MMIO64 1
-#define TIME_SOURCE_MMIO32 2
-#define TIME_SOURCE_FUNCTION 3
-
-/* For proper operations time_interpolator clocks must run slightly slower
- * than the standard clock since the interpolator may only correct by having
- * time jump forward during a tick. A slower clock is usually a side effect
- * of the integer divide of the nanoseconds in a second by the frequency.
- * The accuracy of the division can be increased by specifying a shift.
- * However, this may cause the clock not to be slow enough.
- * The interpolator will self-tune the clock by slowing down if no
- * resets occur or speeding up if the time jumps per analysis cycle
- * become too high.
- *
- * Setting jitter compensates for a fluctuating timesource by comparing
- * to the last value read from the timesource to insure that an earlier value
- * is not returned by a later call. The price to pay
- * for the compensation is that the timer routines are not as scalable anymore.
- */
-
-struct time_interpolator {
- u16 source; /* time source flags */
- u8 shift; /* increases accuracy of multiply by shifting. */
- /* Note that bits may be lost if shift is set too high */
- u8 jitter; /* if set compensate for fluctuations */
- u32 nsec_per_cyc; /* set by register_time_interpolator() */
- void *addr; /* address of counter or function */
- u64 mask; /* mask the valid bits of the counter */
- unsigned long offset; /* nsec offset at last update of interpolator */
- u64 last_counter; /* counter value in units of the counter at last update */
- u64 last_cycle; /* Last timer value if TIME_SOURCE_JITTER is set */
- u64 frequency; /* frequency in counts/second */
- long drift; /* drift in parts-per-million (or -1) */
- unsigned long skips; /* skips forward */
- unsigned long ns_skipped; /* nanoseconds skipped */
- struct time_interpolator *next;
-};
-
-extern void register_time_interpolator(struct time_interpolator *);
-extern void unregister_time_interpolator(struct time_interpolator *);
-extern void time_interpolator_reset(void);
-extern unsigned long time_interpolator_get_offset(void);
-extern void time_interpolator_update(long delta_nsec);
-
-#else /* !CONFIG_TIME_INTERPOLATION */
-
-static inline void time_interpolator_reset(void)
-{
-}
-
-static inline void time_interpolator_update(long delta_nsec)
-{
-}
-
-#endif /* !CONFIG_TIME_INTERPOLATION */
-
#define TICK_LENGTH_SHIFT 32

/* Returns how long ticks are at present, in ns / 2^(SHIFT_SCALE-10). */
diff --exclude=CVS -ur linux-2.6.18-rt6/kernel/time/ntp.c linux-2.6.18-rt6-rmdead/kernel/time/ntp.c
--- linux-2.6.18-rt6/kernel/time/ntp.c 2006-10-19 15:52:47.947971921 +0200
+++ linux-2.6.18-rt6-rmdead/kernel/time/ntp.c 2006-10-19 16:06:20.080065993 +0200
@@ -110,11 +110,6 @@
if (xtime.tv_sec % 86400 == 0) {
xtime.tv_sec--;
wall_to_monotonic.tv_sec++;
- /*
- * The timer interpolator will make time change
- * gradually instead of an immediate jump by one second
- */
- time_interpolator_update(-NSEC_PER_SEC);
time_state = TIME_OOP;
clock_was_set();
printk(KERN_NOTICE "Clock: inserting leap second "
@@ -125,11 +120,6 @@
if ((xtime.tv_sec + 1) % 86400 == 0) {
xtime.tv_sec++;
wall_to_monotonic.tv_sec--;
- /*
- * Use of time interpolator for a gradual change of
- * time
- */
- time_interpolator_update(NSEC_PER_SEC);
time_state = TIME_WAIT;
clock_was_set();
printk(KERN_NOTICE "Clock: deleting leap second "
diff --exclude=CVS -ur linux-2.6.18-rt6/kernel/time.c linux-2.6.18-rt6-rmdead/kernel/time.c
--- linux-2.6.18-rt6/kernel/time.c 2006-10-19 15:52:47.945972354 +0200
+++ linux-2.6.18-rt6-rmdead/kernel/time.c 2006-10-19 16:06:47.833058925 +0200
@@ -134,7 +134,6 @@
write_seqlock_irq(&xtime_lock);
wall_to_monotonic.tv_sec -= sys_tz.tz_minuteswest * 60;
xtime.tv_sec += sys_tz.tz_minuteswest * 60;
- time_interpolator_reset();
warp_check_clock_was_changed();
write_sequnlock_irq(&xtime_lock);
clock_was_set();
@@ -277,81 +276,6 @@
return t;
}
EXPORT_SYMBOL(timespec_trunc);
-
-#ifdef CONFIG_TIME_INTERPOLATION
-void getnstimeofday (struct timespec *tv)
-{
- unsigned long seq,sec,nsec;
-
- do {
- seq = read_seqbegin(&xtime_lock);
- sec = xtime.tv_sec;
- nsec = xtime.tv_nsec+time_interpolator_get_offset();
- } while (unlikely(read_seqretry(&xtime_lock, seq)));
-
- while (unlikely(nsec >= NSEC_PER_SEC)) {
- nsec -= NSEC_PER_SEC;
- ++sec;
- }
- tv->tv_sec = sec;
- tv->tv_nsec = nsec;
-}
-EXPORT_SYMBOL_GPL(getnstimeofday);
-
-int do_settimeofday (struct timespec *tv)
-{
- time_t wtm_sec, sec = tv->tv_sec;
- long wtm_nsec, nsec = tv->tv_nsec;
-
- if ((unsigned long)tv->tv_nsec >= NSEC_PER_SEC)
- return -EINVAL;
-
- write_seqlock_irq(&xtime_lock);
- {
- wtm_sec = wall_to_monotonic.tv_sec + (xtime.tv_sec - sec);
- wtm_nsec = wall_to_monotonic.tv_nsec + (xtime.tv_nsec - nsec);
-
- set_normalized_timespec(&xtime, sec, nsec);
- set_normalized_timespec(&wall_to_monotonic, wtm_sec, wtm_nsec);
-
- time_adjust = 0; /* stop active adjtime() */
- time_status |= STA_UNSYNC;
- time_maxerror = NTP_PHASE_LIMIT;
- time_esterror = NTP_PHASE_LIMIT;
- time_interpolator_reset();
- }
- warp_check_clock_was_changed();
- write_sequnlock_irq(&xtime_lock);
- clock_was_set();
- return 0;
-}
-EXPORT_SYMBOL(do_settimeofday);
-
-void do_gettimeofday (struct timeval *tv)
-{
- unsigned long seq, nsec, usec, sec, offset;
- do {
- seq = read_seqbegin(&xtime_lock);
- offset = time_interpolator_get_offset();
- sec = xtime.tv_sec;
- nsec = xtime.tv_nsec;
- } while (unlikely(read_seqretry(&xtime_lock, seq)));
-
- usec = (nsec + offset) / 1000;
-
- while (unlikely(usec >= USEC_PER_SEC)) {
- usec -= USEC_PER_SEC;
- ++sec;
- }
-
- tv->tv_sec = sec;
- tv->tv_usec = usec;
-}
-
-EXPORT_SYMBOL(do_gettimeofday);
-
-
-#else
#ifndef CONFIG_GENERIC_TIME
/*
* Simulate gettimeofday using do_gettimeofday which only allows a timeval
@@ -367,7 +291,6 @@
}
EXPORT_SYMBOL_GPL(getnstimeofday);
#endif
-#endif

/* Converts Gregorian date to seconds since 1970-01-01 00:00:00.
* Assumes input in normal date format, i.e. 1980-12-31 23:59:59
diff --exclude=CVS -ur linux-2.6.18-rt6/kernel/timer.c linux-2.6.18-rt6-rmdead/kernel/timer.c
--- linux-2.6.18-rt6/kernel/timer.c 2006-10-19 15:52:47.950971271 +0200
+++ linux-2.6.18-rt6-rmdead/kernel/timer.c 2006-10-19 16:06:55.523394356 +0200
@@ -1145,10 +1145,6 @@
second_overflow();
}

- /* interpolator bits */
- time_interpolator_update((clock->xtime_interval
- >> clock->shift)<<shift);
-
/* accumulate error between NTP and clock interval */
clock->error += current_tick_length() << shift;
clock->error -= (clock->xtime_interval
@@ -1736,194 +1732,6 @@
open_softirq(TIMER_SOFTIRQ, run_timer_softirq, NULL);
}

-#ifdef CONFIG_TIME_INTERPOLATION
-
-struct time_interpolator *time_interpolator __read_mostly;
-static struct time_interpolator *time_interpolator_list __read_mostly;
-static DEFINE_SPINLOCK(time_interpolator_lock);
-
-static inline u64 time_interpolator_get_cycles(unsigned int src)
-{
- unsigned long (*x)(void);
-
- switch (src)
- {
- case TIME_SOURCE_FUNCTION:
- x = time_interpolator->addr;
- return x();
-
- case TIME_SOURCE_MMIO64 :
- return readq_relaxed((void __iomem *)time_interpolator->addr);
-
- case TIME_SOURCE_MMIO32 :
- return readl_relaxed((void __iomem *)time_interpolator->addr);
-
- default: return get_cycles();
- }
-}
-
-static inline u64 time_interpolator_get_counter(int writelock)
-{
- unsigned int src = time_interpolator->source;
-
- if (time_interpolator->jitter)
- {
- u64 lcycle;
- u64 now;
-
- do {
- lcycle = time_interpolator->last_cycle;
- now = time_interpolator_get_cycles(src);
- if (lcycle && time_after(lcycle, now))
- return lcycle;
-
- /* When holding the xtime write lock, there's no need
- * to add the overhead of the cmpxchg. Readers are
- * force to retry until the write lock is released.
- */
- if (writelock) {
- time_interpolator->last_cycle = now;
- return now;
- }
- /* Keep track of the last timer value returned. The use of cmpxchg here
- * will cause contention in an SMP environment.
- */
- } while (unlikely(cmpxchg(&time_interpolator->last_cycle, lcycle, now) != lcycle));
- return now;
- }
- else
- return time_interpolator_get_cycles(src);
-}
-
-void time_interpolator_reset(void)
-{
- time_interpolator->offset = 0;
- time_interpolator->last_counter = time_interpolator_get_counter(1);
-}
-
-#define GET_TI_NSECS(count,i) (((((count) - i->last_counter) & (i)->mask) * (i)->nsec_per_cyc) >> (i)->shift)
-
-unsigned long time_interpolator_get_offset(void)
-{
- /* If we do not have a time interpolator set up then just return zero */
- if (!time_interpolator)
- return 0;
-
- return time_interpolator->offset +
- GET_TI_NSECS(time_interpolator_get_counter(0), time_interpolator);
-}
-
-#define INTERPOLATOR_ADJUST 65536
-#define INTERPOLATOR_MAX_SKIP 10*INTERPOLATOR_ADJUST
-
-void time_interpolator_update(long delta_nsec)
-{
- u64 counter;
- unsigned long offset;
-
- /* If there is no time interpolator set up then do nothing */
- if (!time_interpolator)
- return;
-
- /*
- * The interpolator compensates for late ticks by accumulating the late
- * time in time_interpolator->offset. A tick earlier than expected will
- * lead to a reset of the offset and a corresponding jump of the clock
- * forward. Again this only works if the interpolator clock is running
- * slightly slower than the regular clock and the tuning logic insures
- * that.
- */
-
- counter = time_interpolator_get_counter(1);
- offset = time_interpolator->offset +
- GET_TI_NSECS(counter, time_interpolator);
-
- if (delta_nsec < 0 || (unsigned long) delta_nsec < offset)
- time_interpolator->offset = offset - delta_nsec;
- else {
- time_interpolator->skips++;
- time_interpolator->ns_skipped += delta_nsec - offset;
- time_interpolator->offset = 0;
- }
- time_interpolator->last_counter = counter;
-
- /* Tuning logic for time interpolator invoked every minute or so.
- * Decrease interpolator clock speed if no skips occurred and an offset is carried.
- * Increase interpolator clock speed if we skip too much time.
- */
- if (jiffies % INTERPOLATOR_ADJUST == 0)
- {
- if (time_interpolator->skips == 0 && time_interpolator->offset > tick_nsec)
- time_interpolator->nsec_per_cyc--;
- if (time_interpolator->ns_skipped > INTERPOLATOR_MAX_SKIP && time_interpolator->offset == 0)
- time_interpolator->nsec_per_cyc++;
- time_interpolator->skips = 0;
- time_interpolator->ns_skipped = 0;
- }
-}
-
-static inline int
-is_better_time_interpolator(struct time_interpolator *new)
-{
- if (!time_interpolator)
- return 1;
- return new->frequency > 2*time_interpolator->frequency ||
- (unsigned long)new->drift < (unsigned long)time_interpolator->drift;
-}
-
-void
-register_time_interpolator(struct time_interpolator *ti)
-{
- unsigned long flags;
-
- /* Sanity check */
- BUG_ON(ti->frequency == 0 || ti->mask == 0);
-
- ti->nsec_per_cyc = ((u64)NSEC_PER_SEC << ti->shift) / ti->frequency;
- spin_lock(&time_interpolator_lock);
- write_seqlock_irqsave(&xtime_lock, flags);
- if (is_better_time_interpolator(ti)) {
- time_interpolator = ti;
- time_interpolator_reset();
- }
- write_sequnlock_irqrestore(&xtime_lock, flags);
-
- ti->next = time_interpolator_list;
- time_interpolator_list = ti;
- spin_unlock(&time_interpolator_lock);
-}
-
-void
-unregister_time_interpolator(struct time_interpolator *ti)
-{
- struct time_interpolator *curr, **prev;
- unsigned long flags;
-
- spin_lock(&time_interpolator_lock);
- prev = &time_interpolator_list;
- for (curr = *prev; curr; curr = curr->next) {
- if (curr == ti) {
- *prev = curr->next;
- break;
- }
- prev = &curr->next;
- }
-
- write_seqlock_irqsave(&xtime_lock, flags);
- if (ti == time_interpolator) {
- /* we lost the best time-interpolator: */
- time_interpolator = NULL;
- /* find the next-best interpolator */
- for (curr = time_interpolator_list; curr; curr = curr->next)
- if (is_better_time_interpolator(curr))
- time_interpolator = curr;
- time_interpolator_reset();
- }
- write_sequnlock_irqrestore(&xtime_lock, flags);
- spin_unlock(&time_interpolator_lock);
-}
-#endif /* CONFIG_TIME_INTERPOLATION */
-
/**
* msleep - sleep safely even with waitqueue interruptions
* @msecs: Time in milliseconds to sleep for
-
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