[PATCH 1/2] ia64: convert to use clocksource code

From: Peter Keilty
Date: Thu May 10 2007 - 12:46:20 EST

From: Peter Keilty <peter.keilty@xxxxxx>

Initial ia64 conversion to the generic timekeeping/clocksource code.
Performance measurements for single calls (ITC cycles):

A. 32 way Intel IA64 SMP system 8640 (montecito)
A.1. Current code itc cmpxchg
gettimeofday cycles: 39 37 37 37 37 37 37 37 37 37
clock_gettime(REAL) cycles: 49 35 35 35 35 35 35 35 35 35
clock_gettime(MONO) cycles: 42 36 36 36 36 36 36 36 36 36

A.2 New code itc cmpxchg
gettimeofday cycles: 39 38 37 37 38 37 38 37 37 37
clock_gettime(REAL) cycles: 53 35 35 36 35 35 35 35 35 35
clock_gettime(MONO) cycles: 44 38 36 36 36 36 36 36 36 36

A.3 New code itc cmpxchg switched off (nojitter kernel option)
gettimeofday cycles: 35 35 36 35 36 35 36 35 35 35
clock_gettime(REAL) cycles: 49 33 33 34 33 33 33 33 33 33
clock_gettime(MONO) cycles: 38 33 33 33 33 33 33 33 33 33

A.4 New code with hpet as clocksource, mmio space read

Signed-off-by: Peter Keilty <peter.keilty@xxxxxx>
Signed-off-by: John Stultz <johnstul@xxxxxxxxxx>
Signed-off-by: Peter Keilty <peter.keilty@xxxxxx>

---

arch/ia64/Kconfig | 6 +
arch/ia64/configs/bigsur_defconfig | 2
arch/ia64/configs/gensparse_defconfig | 2
arch/ia64/configs/sim_defconfig | 2
arch/ia64/configs/sn2_defconfig | 2
arch/ia64/configs/tiger_defconfig | 2
arch/ia64/configs/zx1_defconfig | 2
arch/ia64/defconfig | 2
arch/ia64/kernel/asm-offsets.c | 23 ++----
arch/ia64/kernel/cyclone.c | 46 +++++++++----
arch/ia64/kernel/fsys.S | 119 +++++++++++++++-------------------
arch/ia64/kernel/fsyscall_gtod_data.h | 18 +++++
arch/ia64/kernel/time.c | 85 ++++++++++++++++++++++--
arch/ia64/sn/kernel/sn2/timer.c | 29 ++++++--
drivers/acpi/processor_idle.c | 4 -
drivers/char/hpet.c | 70 +++++++++++---------
include/linux/clocksource.h | 6 +
17 files changed, 272 insertions(+), 148 deletions(-)

linux-2.6.21-git12_timeofday-arch-ia64_C7.patch
============================================
diff --git a/arch/ia64/Kconfig b/arch/ia64/Kconfig
index d51f0f1..9a7260a 100644
Index: Linux/arch/ia64/Kconfig
===================================================================
--- Linux.orig/arch/ia64/Kconfig 2007-05-10 09:23:51.000000000 -0400
+++ Linux/arch/ia64/Kconfig 2007-05-10 09:27:25.000000000 -0400
@@ -58,7 +58,11 @@ config GENERIC_CALIBRATE_DELAY
bool
default y

-config TIME_INTERPOLATION
+config GENERIC_TIME
+ bool
+ default y
+
+config GENERIC_TIME_VSYSCALL
bool
default y

Index: Linux/arch/ia64/configs/bigsur_defconfig
===================================================================
--- Linux.orig/arch/ia64/configs/bigsur_defconfig 2007-05-10 09:20:35.000000000 -0400
+++ Linux/arch/ia64/configs/bigsur_defconfig 2007-05-10 09:27:25.000000000 -0400
@@ -85,7 +85,7 @@ CONFIG_MMU=y
CONFIG_SWIOTLB=y
CONFIG_RWSEM_XCHGADD_ALGORITHM=y
CONFIG_GENERIC_CALIBRATE_DELAY=y
-CONFIG_TIME_INTERPOLATION=y
+CONFIG_GENERIC_TIME=y
CONFIG_EFI=y
CONFIG_GENERIC_IOMAP=y
CONFIG_SCHED_NO_NO_OMIT_FRAME_POINTER=y
Index: Linux/arch/ia64/configs/gensparse_defconfig
===================================================================
--- Linux.orig/arch/ia64/configs/gensparse_defconfig 2007-05-10 09:20:35.000000000 -0400
+++ Linux/arch/ia64/configs/gensparse_defconfig 2007-05-10 09:27:25.000000000 -0400
@@ -86,7 +86,7 @@ CONFIG_MMU=y
CONFIG_SWIOTLB=y
CONFIG_RWSEM_XCHGADD_ALGORITHM=y
CONFIG_GENERIC_CALIBRATE_DELAY=y
-CONFIG_TIME_INTERPOLATION=y
+CONFIG_GENERIC_TIME=y
CONFIG_EFI=y
CONFIG_GENERIC_IOMAP=y
CONFIG_SCHED_NO_NO_OMIT_FRAME_POINTER=y
Index: Linux/arch/ia64/configs/sim_defconfig
===================================================================
--- Linux.orig/arch/ia64/configs/sim_defconfig 2007-05-10 09:20:35.000000000 -0400
+++ Linux/arch/ia64/configs/sim_defconfig 2007-05-10 09:27:25.000000000 -0400
@@ -86,7 +86,7 @@ CONFIG_MMU=y
CONFIG_SWIOTLB=y
CONFIG_RWSEM_XCHGADD_ALGORITHM=y
CONFIG_GENERIC_CALIBRATE_DELAY=y
-CONFIG_TIME_INTERPOLATION=y
+CONFIG_GENERIC_TIME=y
CONFIG_EFI=y
CONFIG_GENERIC_IOMAP=y
CONFIG_SCHED_NO_NO_OMIT_FRAME_POINTER=y
Index: Linux/arch/ia64/configs/sn2_defconfig
===================================================================
--- Linux.orig/arch/ia64/configs/sn2_defconfig 2007-05-10 09:20:35.000000000 -0400
+++ Linux/arch/ia64/configs/sn2_defconfig 2007-05-10 09:27:25.000000000 -0400
@@ -93,7 +93,7 @@ CONFIG_SWIOTLB=y
CONFIG_RWSEM_XCHGADD_ALGORITHM=y
CONFIG_GENERIC_FIND_NEXT_BIT=y
CONFIG_GENERIC_CALIBRATE_DELAY=y
-CONFIG_TIME_INTERPOLATION=y
+CONFIG_GENERIC_TIME=y
CONFIG_DMI=y
CONFIG_EFI=y
CONFIG_GENERIC_IOMAP=y
Index: Linux/arch/ia64/kernel/asm-offsets.c
===================================================================
--- Linux.orig/arch/ia64/kernel/asm-offsets.c 2007-05-10 09:20:35.000000000 -0400
+++ Linux/arch/ia64/kernel/asm-offsets.c 2007-05-10 09:27:25.000000000 -0400
@@ -7,6 +7,7 @@
#define ASM_OFFSETS_C 1

#include <linux/sched.h>
+#include <linux/clocksource.h>

#include <asm-ia64/processor.h>
#include <asm-ia64/ptrace.h>
@@ -15,6 +16,7 @@
#include <asm-ia64/mca.h>

#include "../kernel/sigframe.h"
+#include "../kernel/fsyscall_gtod_data.h"

#define DEFINE(sym, val) \
asm volatile("\n->" #sym " %0 " #val : : "i" (val))
@@ -256,17 +258,12 @@ void foo(void)
BLANK();

/* used by fsys_gettimeofday in arch/ia64/kernel/fsys.S */
- DEFINE(IA64_TIME_INTERPOLATOR_ADDRESS_OFFSET, offsetof (struct time_interpolator, addr));
- DEFINE(IA64_TIME_INTERPOLATOR_SOURCE_OFFSET, offsetof (struct time_interpolator, source));
- DEFINE(IA64_TIME_INTERPOLATOR_SHIFT_OFFSET, offsetof (struct time_interpolator, shift));
- DEFINE(IA64_TIME_INTERPOLATOR_NSEC_OFFSET, offsetof (struct time_interpolator, nsec_per_cyc));
- DEFINE(IA64_TIME_INTERPOLATOR_OFFSET_OFFSET, offsetof (struct time_interpolator, offset));
- DEFINE(IA64_TIME_INTERPOLATOR_LAST_CYCLE_OFFSET, offsetof (struct time_interpolator, last_cycle));
- DEFINE(IA64_TIME_INTERPOLATOR_LAST_COUNTER_OFFSET, offsetof (struct time_interpolator, last_counter));
- DEFINE(IA64_TIME_INTERPOLATOR_JITTER_OFFSET, offsetof (struct time_interpolator, jitter));
- DEFINE(IA64_TIME_INTERPOLATOR_MASK_OFFSET, offsetof (struct time_interpolator, mask));
- DEFINE(IA64_TIME_SOURCE_CPU, TIME_SOURCE_CPU);
- DEFINE(IA64_TIME_SOURCE_MMIO64, TIME_SOURCE_MMIO64);
- DEFINE(IA64_TIME_SOURCE_MMIO32, TIME_SOURCE_MMIO32);
- DEFINE(IA64_TIMESPEC_TV_NSEC_OFFSET, offsetof (struct timespec, tv_nsec));
+ DEFINE(IA64_GTOD_LOCK_OFFSET, offsetof (struct fsyscall_gtod_data_t, lock));
+ DEFINE(IA64_CLKSRC_MASK_OFFSET, offsetof (struct fsyscall_gtod_data_t, clk_mask));
+ DEFINE(IA64_CLKSRC_MULT_OFFSET, offsetof (struct fsyscall_gtod_data_t, clk_mult));
+ DEFINE(IA64_CLKSRC_SHIFT_OFFSET, offsetof (struct fsyscall_gtod_data_t, clk_shift));
+ DEFINE(IA64_CLKSRC_MMIO_OFFSET, offsetof (struct fsyscall_gtod_data_t, clk_fsys_mmio));
+ DEFINE(IA64_CLKSRC_CYCLE_LAST_OFFSET, offsetof (struct fsyscall_gtod_data_t, clk_cycle_last));
+ DEFINE(IA64_ITC_LASTCYCLE_OFFSET, offsetof (struct fsyscall_gtod_data_t, itc_lastcycle));
+ DEFINE(IA64_ITC_JITTER_OFFSET, offsetof (struct fsyscall_gtod_data_t, itc_jitter));
}
Index: Linux/arch/ia64/kernel/cyclone.c
===================================================================
--- Linux.orig/arch/ia64/kernel/cyclone.c 2007-05-10 09:20:35.000000000 -0400
+++ Linux/arch/ia64/kernel/cyclone.c 2007-05-10 09:27:25.000000000 -0400
@@ -3,6 +3,7 @@
#include <linux/time.h>
#include <linux/errno.h>
#include <linux/timex.h>
+#include <linux/clocksource.h>
#include <asm/io.h>

/* IBM Summit (EXA) Cyclone counter code*/
@@ -18,13 +19,21 @@ void __init cyclone_setup(void)
use_cyclone = 1;
}

+static void __iomem *cyclone_mc;

-struct time_interpolator cyclone_interpolator = {
- .source = TIME_SOURCE_MMIO64,
- .shift = 16,
- .frequency = CYCLONE_TIMER_FREQ,
- .drift = -100,
- .mask = (1LL << 40) - 1
+static cycle_t read_cyclone(void)
+{
+ return (cycle_t)readq((void __iomem *)cyclone_mc);
+}
+
+static struct clocksource clocksource_cyclone = {
+ .name = "cyclone",
+ .rating = 300,
+ .read = read_cyclone,
+ .mask = (1LL << 40) - 1,
+ .mult = 0, /*to be caluclated*/
+ .shift = 16,
+ .flags = CLOCK_SOURCE_IS_CONTINUOUS,
};

int __init init_cyclone_clock(void)
@@ -44,13 +53,15 @@ int __init init_cyclone_clock(void)
offset = (CYCLONE_CBAR_ADDR);
reg = (u64*)ioremap_nocache(offset, sizeof(u64));
if(!reg){
- printk(KERN_ERR "Summit chipset: Could not find valid CBAR register.\n");
+ printk(KERN_ERR "Summit chipset: Could not find valid CBAR"
+ " register.\n");
use_cyclone = 0;
return -ENODEV;
}
base = readq(reg);
if(!base){
- printk(KERN_ERR "Summit chipset: Could not find valid CBAR value.\n");
+ printk(KERN_ERR "Summit chipset: Could not find valid CBAR"
+ " value.\n");
use_cyclone = 0;
return -ENODEV;
}
@@ -60,7 +71,8 @@ int __init init_cyclone_clock(void)
offset = (base + CYCLONE_PMCC_OFFSET);
reg = (u64*)ioremap_nocache(offset, sizeof(u64));
if(!reg){
- printk(KERN_ERR "Summit chipset: Could not find valid PMCC register.\n");
+ printk(KERN_ERR "Summit chipset: Could not find valid PMCC"
+ " register.\n");
use_cyclone = 0;
return -ENODEV;
}
@@ -71,7 +83,8 @@ int __init init_cyclone_clock(void)
offset = (base + CYCLONE_MPCS_OFFSET);
reg = (u64*)ioremap_nocache(offset, sizeof(u64));
if(!reg){
- printk(KERN_ERR "Summit chipset: Could not find valid MPCS register.\n");
+ printk(KERN_ERR "Summit chipset: Could not find valid MPCS"
+ " register.\n");
use_cyclone = 0;
return -ENODEV;
}
@@ -82,7 +95,8 @@ int __init init_cyclone_clock(void)
offset = (base + CYCLONE_MPMC_OFFSET);
cyclone_timer = (u32*)ioremap_nocache(offset, sizeof(u32));
if(!cyclone_timer){
- printk(KERN_ERR "Summit chipset: Could not find valid MPMC register.\n");
+ printk(KERN_ERR "Summit chipset: Could not find valid MPMC"
+ " register.\n");
use_cyclone = 0;
return -ENODEV;
}
@@ -93,7 +107,8 @@ int __init init_cyclone_clock(void)
int stall = 100;
while(stall--) barrier();
if(readl(cyclone_timer) == old){
- printk(KERN_ERR "Summit chipset: Counter not counting! DISABLED\n");
+ printk(KERN_ERR "Summit chipset: Counter not counting!"
+ " DISABLED\n");
iounmap(cyclone_timer);
cyclone_timer = 0;
use_cyclone = 0;
@@ -101,8 +116,11 @@ int __init init_cyclone_clock(void)
}
}
/* initialize last tick */
- cyclone_interpolator.addr = cyclone_timer;
- register_time_interpolator(&cyclone_interpolator);
+ cyclone_mc = cyclone_timer;
+ clocksource_cyclone.fsys_mmio = cyclone_timer;
+ clocksource_cyclone.mult = clocksource_hz2mult(CYCLONE_TIMER_FREQ,
+ clocksource_cyclone.shift);
+ clocksource_register(&clocksource_cyclone);

return 0;
}
Index: Linux/arch/ia64/kernel/fsys.S
===================================================================
--- Linux.orig/arch/ia64/kernel/fsys.S 2007-05-10 09:20:35.000000000 -0400
+++ Linux/arch/ia64/kernel/fsys.S 2007-05-10 09:27:25.000000000 -0400
@@ -147,12 +147,8 @@ ENTRY(fsys_set_tid_address)
FSYS_RETURN
END(fsys_set_tid_address)

-/*
- * Ensure that the time interpolator structure is compatible with the asm code
- */
-#if IA64_TIME_INTERPOLATOR_SOURCE_OFFSET !=0 || IA64_TIME_INTERPOLATOR_SHIFT_OFFSET != 2 \
- || IA64_TIME_INTERPOLATOR_JITTER_OFFSET != 3 || IA64_TIME_INTERPOLATOR_NSEC_OFFSET != 4
-#error fsys_gettimeofday incompatible with changes to struct time_interpolator
+#if IA64_GTOD_LOCK_OFFSET !=0
+#error fsys_gettimeofday incompatible with changes to struct fsyscall_gtod_data_t
#endif
#define CLOCK_REALTIME 0
#define CLOCK_MONOTONIC 1
@@ -179,19 +175,18 @@ ENTRY(fsys_gettimeofday)
// r11 = preserved: saved ar.pfs
// r12 = preserved: memory stack
// r13 = preserved: thread pointer
- // r14 = address of mask / mask
+ // r14 = address of mask / mask value
// r15 = preserved: system call number
// r16 = preserved: current task pointer
// r17 = wall to monotonic use
- // r18 = time_interpolator->offset
- // r19 = address of wall_to_monotonic
- // r20 = pointer to struct time_interpolator / pointer to time_interpolator->address
- // r21 = shift factor
- // r22 = address of time interpolator->last_counter
- // r23 = address of time_interpolator->last_cycle
- // r24 = adress of time_interpolator->offset
- // r25 = last_cycle value
- // r26 = last_counter value
+ // r19 = address of itc_lastcycle
+ // r20 = struct fsyscall_gtod_data / address of first element
+ // r21 = address of mmio_ptr
+ // r22 = address of wall_to_monotonic
+ // r23 = address of shift/ value
+ // 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
@@ -201,10 +196,10 @@ ENTRY(fsys_gettimeofday)
// p6,p7 short term use
// p8 = timesource ar.itc
// p9 = timesource mmio64
- // p10 = timesource mmio32
+ // p10 = timesource mmio32 - not used
// p11 = timesource not to be handled by asm code
- // p12 = memory time source ( = p9 | p10)
- // p13 = do cmpxchg with time_interpolator_last_cycle
+ // p12 = memory time source ( = p9 | p10) - not used
+ // p13 = do cmpxchg with itc_lastcycle
// p14 = Divide by 1000
// p15 = Add monotonic
//
@@ -214,61 +209,56 @@ ENTRY(fsys_gettimeofday)
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 = time_interpolator
+ movl r20 = fsyscall_gtod_data // load fsyscall gettimeofday data address
;;
- ld8 r20 = [r20] // get pointer to time_interpolator structure
- movl r29 = xtime_lock
- ld4 r2 = [r2] // process work pending flags
+ add r29 = IA64_ITC_JITTER_OFFSET,r20
movl r27 = xtime
- ;; // only one bundle here
- ld8 r21 = [r20] // first quad with control information
+ ld4 r2 = [r2] // process work pending flags
+(p15) movl r22 = wall_to_monotonic
+ ;;
+ add r21 = IA64_CLKSRC_MMIO_OFFSET,r20
+ add r19 = IA64_ITC_LASTCYCLE_OFFSET,r20
and r2 = TIF_ALLWORK_MASK,r2
(p6) br.cond.spnt.few .fail_einval // deferred branch
;;
- add r10 = IA64_TIME_INTERPOLATOR_ADDRESS_OFFSET,r20
- extr r3 = r21,32,32 // time_interpolator->nsec_per_cyc
- extr r8 = r21,0,16 // time_interpolator->source
+ add r26 = IA64_CLKSRC_CYCLE_LAST_OFFSET,r20 // clksrc_cycle_last
cmp.ne p6, p0 = 0, r2 // Fallback if work is scheduled
(p6) br.cond.spnt.many fsys_fallback_syscall
- ;;
- cmp.eq p8,p12 = 0,r8 // Check for cpu timer
- cmp.eq p9,p0 = 1,r8 // MMIO64 ?
- extr r2 = r21,24,8 // time_interpolator->jitter
- cmp.eq p10,p0 = 2,r8 // MMIO32 ?
- cmp.ltu p11,p0 = 2,r8 // function or other clock
-(p11) br.cond.spnt.many fsys_fallback_syscall
- ;;
- setf.sig f7 = r3 // Setup for scaling of counter
-(p15) movl r19 = wall_to_monotonic
-(p12) ld8 r30 = [r10]
- cmp.ne p13,p0 = r2,r0 // need jitter compensation?
- extr r21 = r21,16,8 // shift factor
- ;;
+ ;; // get lock.seq here new code, outer loop2!
.time_redo:
- .pred.rel.mutex p8,p9,p10
- ld4.acq r28 = [r29] // xtime_lock.sequence. Must come first for locking purposes
+ ld4.acq r28 = [r20] // gtod_lock.sequence, Must be first in struct
+ ld8 r30 = [r21] // clocksource->mmio_ptr
+ add r24 = IA64_CLKSRC_MULT_OFFSET,r20
+ ld4 r2 = [r29] // itc_jitter value
+ add r23 = IA64_CLKSRC_SHIFT_OFFSET,r20
+ add r14 = IA64_CLKSRC_MASK_OFFSET,r20
+ ;;
+ ld4 r3 = [r24] // clocksource mult value
+ ld8 r14 = [r14] // clocksource mask 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
+(p8) cmp.ne p13,p0 = r2,r0 // need itc_jitter compensation, set p13
+ ld4 r23 = [r23] // clocksource shift value
+ ld8 r24 = [r26] // get clksrc_cycle_last value
+(p9) cmp.eq p13,p0 = 0,r30 // if mmio_ptr, clear p13 jitter control
+ ;; // old position for lock seq, new inner loop1!
+.cmpxchg_redo:
+ .pred.rel.mutex p8,p9
(p8) mov r2 = ar.itc // CPU_TIMER. 36 clocks latency!!!
- add r22 = IA64_TIME_INTERPOLATOR_LAST_COUNTER_OFFSET,r20
(p9) ld8 r2 = [r30] // readq(ti->address). Could also have latency issues..
-(p10) ld4 r2 = [r30] // readw(ti->address)
-(p13) add r23 = IA64_TIME_INTERPOLATOR_LAST_CYCLE_OFFSET,r20
+(p13) ld8 r25 = [r19] // get itc_lastcycle value
;; // could be removed by moving the last add upward
- ld8 r26 = [r22] // time_interpolator->last_counter
-(p13) ld8 r25 = [r23] // time interpolator->last_cycle
- add r24 = IA64_TIME_INTERPOLATOR_OFFSET_OFFSET,r20
-(p15) ld8 r17 = [r19],IA64_TIMESPEC_TV_NSEC_OFFSET
ld8 r9 = [r27],IA64_TIMESPEC_TV_NSEC_OFFSET
- add r14 = IA64_TIME_INTERPOLATOR_MASK_OFFSET, r20
+(p15) ld8 r17 = [r22],IA64_TIMESPEC_TV_NSEC_OFFSET
;;
- ld8 r18 = [r24] // time_interpolator->offset
ld8 r8 = [r27],-IA64_TIMESPEC_TV_NSEC_OFFSET // xtime.tv_nsec
-(p13) sub r3 = r25,r2 // Diff needed before comparison (thanks davidm)
+(p13) sub r3 = r25,r2 // Diff needed before comparison (thanks davidm)
;;
- ld8 r14 = [r14] // time_interpolator->mask
-(p13) cmp.gt.unc p6,p7 = r3,r0 // check if it is less than last. p6,p7 cleared
- sub r10 = r2,r26 // current_counter - last_counter
+(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,r26 // time we got was less than last_cycle
+(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
@@ -276,27 +266,28 @@ ENTRY(fsys_gettimeofday)
setf.sig f8 = r10
nop.i 123
;;
-(p7) cmpxchg8.rel r3 = [r23],r2,ar.ccv
+(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 = [r19],-IA64_TIMESPEC_TV_NSEC_OFFSET
+ // End cmpxchg critical section loop1
+(p15) ld8 r17 = [r22],-IA64_TIMESPEC_TV_NSEC_OFFSET
(p7) cmp.ne p7,p0 = r25,r3 // if cmpxchg not successful redo
+(p7) br.cond.dpnt.few .cmpxchg_redo // inner loop1
// 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
- add r8 = r8,r18 // Add time interpolator offset
;;
- ld4 r10 = [r29] // xtime_lock.sequence
+ ld4 r10 = [r20] // gtod_lock.sequence, old xtime_lock.sequence
(p15) add r8 = r8, r17 // Add monotonic.nsecs to nsecs
- shr.u r2 = r2,r21
+ shr.u r2 = r2,r23 // 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 ?
+(p7) br.cond.dpnt.few .time_redo // sequence number changed, outer loop2
// Now r8=tv->tv_nsec and r9=tv->tv_sec
mov r10 = r0
movl r2 = 1000000000
Index: Linux/arch/ia64/kernel/time.c
===================================================================
--- Linux.orig/arch/ia64/kernel/time.c 2007-05-10 09:23:51.000000000 -0400
+++ Linux/arch/ia64/kernel/time.c 2007-05-10 09:27:25.000000000 -0400
@@ -20,6 +20,7 @@
#include <linux/efi.h>
#include <linux/profile.h>
#include <linux/timex.h>
+#include <linux/clocksource.h>

#include <asm/machvec.h>
#include <asm/delay.h>
@@ -29,6 +30,14 @@
#include <asm/sections.h>
#include <asm/system.h>

+#include "fsyscall_gtod_data.h"
+
+static cycle_t itc_get_cycles(void);
+
+struct fsyscall_gtod_data_t fsyscall_gtod_data = {
+ .lock = SEQLOCK_UNLOCKED,
+};
+
volatile int time_keeper_id = 0; /* smp_processor_id() of time-keeper */

#ifdef CONFIG_IA64_DEBUG_IRQ
@@ -38,11 +47,16 @@ EXPORT_SYMBOL(last_cli_ip);

#endif

-static struct time_interpolator itc_interpolator = {
- .shift = 16,
- .mask = 0xffffffffffffffffLL,
- .source = TIME_SOURCE_CPU
+static struct clocksource clocksource_itc = {
+ .name = "itc",
+ .rating = 350,
+ .read = itc_get_cycles,
+ .mask = 0xffffffffffffffff,
+ .mult = 0, /*to be caluclated*/
+ .shift = 16,
+ .flags = CLOCK_SOURCE_IS_CONTINUOUS,
};
+static struct clocksource *itc_clocksource;

static irqreturn_t
timer_interrupt (int irq, void *dev_id)
@@ -211,8 +225,6 @@ ia64_init_itm (void)
+ itc_freq/2)/itc_freq;

if (!(sal_platform_features & IA64_SAL_PLATFORM_FEATURE_ITC_DRIFT)) {
- itc_interpolator.frequency = local_cpu_data->itc_freq;
- itc_interpolator.drift = itc_drift;
#ifdef CONFIG_SMP
/* On IA64 in an SMP configuration ITCs are never accurately synchronized.
* Jitter compensation requires a cmpxchg which may limit
@@ -224,15 +236,55 @@ ia64_init_itm (void)
* even going backward) if the ITC offsets between the individual CPUs
* are too large.
*/
- if (!nojitter) itc_interpolator.jitter = 1;
+ if (!nojitter)
+ fsyscall_gtod_data.itc_jitter = 1;
#endif
- register_time_interpolator(&itc_interpolator);
}

/* Setup the CPU local timer tick */
ia64_cpu_local_tick();
+
+ if (!itc_clocksource) {
+ /* Sort out mult/shift values: */
+ clocksource_itc.mult =
+ clocksource_hz2mult(local_cpu_data->itc_freq,
+ clocksource_itc.shift);
+ clocksource_register(&clocksource_itc);
+ itc_clocksource = &clocksource_itc;
+ }
}

+static cycle_t itc_get_cycles()
+{
+ u64 lcycle;
+ u64 now;
+
+ if (!fsyscall_gtod_data.itc_jitter)
+ return get_cycles();
+ do {
+ lcycle = fsyscall_gtod_data.itc_lastcycle;
+ now = get_cycles();
+ 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 (spin_is_locked(&xtime_lock.lock)) {
+ fsyscall_gtod_data.itc_lastcycle = now;
+ return now;
+ }
+ /* Keep track of the last timer value returned.
+ * The use of cmpxchg here will cause contention in
+ * an SMP environment.
+ */
+ } while (likely(cmpxchg(&fsyscall_gtod_data.itc_lastcycle,
+ lcycle, now) != lcycle));
+ return now;
+}
+
+
static struct irqaction timer_irqaction = {
.handler = timer_interrupt,
.flags = IRQF_DISABLED | IRQF_IRQPOLL,
@@ -308,3 +360,20 @@ ia64_setup_printk_clock(void)
if (!(sal_platform_features & IA64_SAL_PLATFORM_FEATURE_ITC_DRIFT))
ia64_printk_clock = ia64_itc_printk_clock;
}
+
+void update_vsyscall(struct timespec *wall, struct clocksource *c)
+{
+ unsigned long flags;
+
+ write_seqlock_irqsave(&fsyscall_gtod_data.lock, flags);
+
+ /* copy fsyscall clock data */
+ fsyscall_gtod_data.clk_mask = c->mask;
+ fsyscall_gtod_data.clk_mult = c->mult;
+ fsyscall_gtod_data.clk_shift = c->shift;
+ fsyscall_gtod_data.clk_fsys_mmio = c->fsys_mmio;
+ fsyscall_gtod_data.clk_cycle_last = c->cycle_last;
+
+ write_sequnlock_irqrestore(&fsyscall_gtod_data.lock, flags);
+}
+
Index: Linux/arch/ia64/sn/kernel/sn2/timer.c
===================================================================
--- Linux.orig/arch/ia64/sn/kernel/sn2/timer.c 2007-05-10 09:20:35.000000000 -0400
+++ Linux/arch/ia64/sn/kernel/sn2/timer.c 2007-05-10 09:27:25.000000000 -0400
@@ -11,6 +11,7 @@
#include <linux/sched.h>
#include <linux/time.h>
#include <linux/interrupt.h>
+#include <linux/clocksource.h>

#include <asm/hw_irq.h>
#include <asm/system.h>
@@ -22,11 +23,21 @@

extern unsigned long sn_rtc_cycles_per_second;

-static struct time_interpolator sn2_interpolator = {
- .drift = -1,
- .shift = 10,
- .mask = (1LL << 55) - 1,
- .source = TIME_SOURCE_MMIO64
+static void __iomem *sn2_mc;
+
+static cycle_t read_sn2(void)
+{
+ return (cycle_t)readq(sn2_mc);
+}
+
+static struct clocksource clocksource_sn2 = {
+ .name = "sn2_rtc",
+ .rating = 300,
+ .read = read_sn2,
+ .mask = (1LL << 55) - 1,
+ .mult = 0,
+ .shift = 10,
+ .flags = CLOCK_SOURCE_IS_CONTINUOUS,
};

/*
@@ -47,9 +58,11 @@ ia64_sn_udelay (unsigned long usecs)

void __init sn_timer_init(void)
{
- sn2_interpolator.frequency = sn_rtc_cycles_per_second;
- sn2_interpolator.addr = RTC_COUNTER_ADDR;
- register_time_interpolator(&sn2_interpolator);
+ sn2_mc = RTC_COUNTER_ADDR;
+ clocksource_sn2.fsys_mmio = RTC_COUNTER_ADDR;
+ clocksource_sn2.mult = clocksource_hz2mult(sn_rtc_cycles_per_second,
+ clocksource_sn2.shift);
+ clocksource_register(&clocksource_sn2);

ia64_udelay = &ia64_sn_udelay;
}
Index: Linux/drivers/acpi/processor_idle.c
===================================================================
--- Linux.orig/drivers/acpi/processor_idle.c 2007-05-10 09:23:52.000000000 -0400
+++ Linux/drivers/acpi/processor_idle.c 2007-05-10 09:27:25.000000000 -0400
@@ -473,7 +473,7 @@ static void acpi_processor_idle(void)
/* Get end time (ticks) */
t2 = inl(acpi_gbl_FADT.xpm_timer_block.address);

-#ifdef CONFIG_GENERIC_TIME
+#if defined (CONFIG_GENERIC_TIME) && defined (CONFIG_X86_TSC)
/* TSC halts in C2, so notify users */
mark_tsc_unstable("possible TSC halt in C2");
#endif
@@ -515,7 +515,7 @@ static void acpi_processor_idle(void)
acpi_set_register(ACPI_BITREG_ARB_DISABLE, 0);
}

-#ifdef CONFIG_GENERIC_TIME
+#if defined (CONFIG_GENERIC_TIME) && defined (CONFIG_X86_TSC)
/* TSC halts in C3, so notify users */
mark_tsc_unstable("TSC halts in C3");
#endif
Index: Linux/drivers/char/hpet.c
===================================================================
--- Linux.orig/drivers/char/hpet.c 2007-05-10 09:20:35.000000000 -0400
+++ Linux/drivers/char/hpet.c 2007-05-10 09:27:25.000000000 -0400
@@ -29,6 +29,7 @@
#include <linux/bcd.h>
#include <linux/seq_file.h>
#include <linux/bitops.h>
+#include <linux/clocksource.h>

#include <asm/current.h>
#include <asm/uaccess.h>
@@ -51,8 +52,34 @@

#define HPET_RANGE_SIZE 1024 /* from HPET spec */

+#if BITS_PER_LONG == 64
+#define write_counter(V, MC) writeq(V, MC)
+#define read_counter(MC) readq(MC)
+#else
+#define write_counter(V, MC) writel(V, MC)
+#define read_counter(MC) readl(MC)
+#endif
+
static u32 hpet_nhpet, hpet_max_freq = HPET_USER_FREQ;

+static void __iomem *hpet_mctr;
+
+static cycle_t read_hpet(void)
+{
+ return (cycle_t)read_counter((void __iomem *)hpet_mctr);
+}
+
+static struct clocksource clocksource_hpet = {
+ .name = "hpet",
+ .rating = 250,
+ .read = read_hpet,
+ .mask = 0xffffffffffffffff,
+ .mult = 0, /*to be caluclated*/
+ .shift = 10,
+ .flags = CLOCK_SOURCE_IS_CONTINUOUS,
+};
+static struct clocksource *hpet_clocksource;
+
/* A lock for concurrent access by app and isr hpet activity. */
static DEFINE_SPINLOCK(hpet_lock);
/* A lock for concurrent intermodule access to hpet and isr hpet activity. */
@@ -79,7 +106,7 @@ struct hpets {
struct hpets *hp_next;
struct hpet __iomem *hp_hpet;
unsigned long hp_hpet_phys;
- struct time_interpolator *hp_interpolator;
+ struct clocksource *hp_clocksource;
unsigned long long hp_tick_freq;
unsigned long hp_delta;
unsigned int hp_ntimer;
@@ -94,13 +121,6 @@ static struct hpets *hpets;
#define HPET_PERIODIC 0x0004
#define HPET_SHARED_IRQ 0x0008

-#if BITS_PER_LONG == 64
-#define write_counter(V, MC) writeq(V, MC)
-#define read_counter(MC) readq(MC)
-#else
-#define write_counter(V, MC) writel(V, MC)
-#define read_counter(MC) readl(MC)
-#endif

#ifndef readq
static inline unsigned long long readq(void __iomem *addr)
@@ -737,27 +757,6 @@ static ctl_table dev_root[] = {

static struct ctl_table_header *sysctl_header;

-static void hpet_register_interpolator(struct hpets *hpetp)
-{
-#ifdef CONFIG_TIME_INTERPOLATION
- struct time_interpolator *ti;
-
- ti = kzalloc(sizeof(*ti), GFP_KERNEL);
- if (!ti)
- return;
-
- ti->source = TIME_SOURCE_MMIO64;
- ti->shift = 10;
- ti->addr = &hpetp->hp_hpet->hpet_mc;
- ti->frequency = hpetp->hp_tick_freq;
- ti->drift = HPET_DRIFT;
- ti->mask = -1;
-
- hpetp->hp_interpolator = ti;
- register_time_interpolator(ti);
-#endif
-}
-
/*
* Adjustment for when arming the timer with
* initial conditions. That is, main counter
@@ -909,7 +908,16 @@ int hpet_alloc(struct hpet_data *hdp)
}

hpetp->hp_delta = hpet_calibrate(hpetp);
- hpet_register_interpolator(hpetp);
+
+ if (!hpet_clocksource) {
+ hpet_mctr = (void __iomem *)&hpetp->hp_hpet->hpet_mc;
+ CLKSRC_FSYS_MMIO_SET(clocksource_hpet.fsys_mmio, hpet_mctr);
+ clocksource_hpet.mult = clocksource_hz2mult(hpetp->hp_tick_freq,
+ clocksource_hpet.shift);
+ clocksource_register(&clocksource_hpet);
+ hpetp->hp_clocksource = &clocksource_hpet;
+ hpet_clocksource = &clocksource_hpet;
+ }

return 0;
}
@@ -995,7 +1003,7 @@ static int hpet_acpi_add(struct acpi_dev

static int hpet_acpi_remove(struct acpi_device *device, int type)
{
- /* XXX need to unregister interpolator, dealloc mem, etc */
+ /* XXX need to unregister clocksource, dealloc mem, etc */
return -EINVAL;
}

Index: Linux/include/linux/clocksource.h
===================================================================
--- Linux.orig/include/linux/clocksource.h 2007-05-10 09:23:55.000000000 -0400
+++ Linux/include/linux/clocksource.h 2007-05-10 09:30:42.000000000 -0400
@@ -67,6 +67,12 @@ struct clocksource {
unsigned long flags;
cycle_t (*vread)(void);
void (*resume)(void);
+#ifdef CONFIG_IA64
+ void *fsys_mmio; /* used by fsyscall asm code */
+#define CLKSRC_FSYS_MMIO_SET(mmio, addr) ((mmio) = (addr))
+#else
+#define CLKSRC_FSYS_MMIO_SET(mmio, addr) (0)
+#endif

/* timekeeping specific data, ignore */
cycle_t cycle_interval;
Index: Linux/arch/ia64/configs/tiger_defconfig
===================================================================
--- Linux.orig/arch/ia64/configs/tiger_defconfig 2007-05-10 09:20:35.000000000 -0400
+++ Linux/arch/ia64/configs/tiger_defconfig 2007-05-10 09:27:25.000000000 -0400
@@ -98,7 +98,7 @@ CONFIG_RWSEM_XCHGADD_ALGORITHM=y
# CONFIG_ARCH_HAS_ILOG2_U64 is not set
CONFIG_GENERIC_FIND_NEXT_BIT=y
CONFIG_GENERIC_CALIBRATE_DELAY=y
-CONFIG_TIME_INTERPOLATION=y
+CONFIG_GENERIC_TIME=y
CONFIG_DMI=y
CONFIG_EFI=y
CONFIG_GENERIC_IOMAP=y
Index: Linux/arch/ia64/configs/zx1_defconfig
===================================================================
--- Linux.orig/arch/ia64/configs/zx1_defconfig 2007-05-10 09:20:35.000000000 -0400
+++ Linux/arch/ia64/configs/zx1_defconfig 2007-05-10 09:27:25.000000000 -0400
@@ -96,7 +96,7 @@ CONFIG_RWSEM_XCHGADD_ALGORITHM=y
# CONFIG_ARCH_HAS_ILOG2_U64 is not set
CONFIG_GENERIC_FIND_NEXT_BIT=y
CONFIG_GENERIC_CALIBRATE_DELAY=y
-CONFIG_TIME_INTERPOLATION=y
+CONFIG_GENERIC_TIME=y
CONFIG_DMI=y
CONFIG_EFI=y
CONFIG_GENERIC_IOMAP=y
Index: Linux/arch/ia64/defconfig
===================================================================
--- Linux.orig/arch/ia64/defconfig 2007-05-10 09:23:51.000000000 -0400
+++ Linux/arch/ia64/defconfig 2007-05-10 09:27:25.000000000 -0400
@@ -98,7 +98,7 @@ CONFIG_RWSEM_XCHGADD_ALGORITHM=y
# CONFIG_ARCH_HAS_ILOG2_U64 is not set
CONFIG_GENERIC_FIND_NEXT_BIT=y
CONFIG_GENERIC_CALIBRATE_DELAY=y
-CONFIG_TIME_INTERPOLATION=y
+CONFIG_GENERIC_TIME=y
CONFIG_DMI=y
CONFIG_EFI=y
CONFIG_GENERIC_IOMAP=y
Index: Linux/arch/ia64/kernel/fsyscall_gtod_data.h
===================================================================
--- /dev/null 1970-01-01 00:00:00.000000000 +0000
+++ Linux/arch/ia64/kernel/fsyscall_gtod_data.h 2007-05-10 09:27:25.000000000 -0400
@@ -0,0 +1,18 @@
+/*
+ * (c) Copyright 2007 Hewlett-Packard Development Company, L.P.
+ * Contributed by Peter Keilty <peter.keilty@xxxxxx>
+ *
+ * fsyscall gettimeofday data
+ */
+
+struct fsyscall_gtod_data_t {
+ seqlock_t lock;
+ cycle_t clk_mask;
+ u32 clk_mult;
+ u32 clk_shift;
+ void *clk_fsys_mmio;
+ cycle_t clk_cycle_last;
+ cycle_t itc_lastcycle;
+ int itc_jitter;
+} __attribute__ ((aligned (L1_CACHE_BYTES)));
+
-
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