lockmeter port for ppc64

From: tdgarcia
Date: Tue Nov 01 2005 - 17:53:16 EST

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My team and I adapted your lockmeter code to the ppc64 architecture. I am attaching the ppc64 specific code to this email. This code should patch cleanly to the 2.6.13 kernel.

diff -Narup linux-2.6.13/arch/ppc64/Kconfig.debug linux-2.6.13-lockmeter/arch/ppc64/Kconfig.debug
--- linux-2.6.13/arch/ppc64/Kconfig.debug 2005-08-28 16:41:01.000000000 -0700
+++ linux-2.6.13-lockmeter/arch/ppc64/Kconfig.debug 2005-10-11 07:40:28.000000000 -0700
@@ -19,6 +19,13 @@ config KPROBES
for kernel debugging, non-intrusive instrumentation and testing.
If in doubt, say "N".

+config LOCKMETER
+ bool "Kernel lock metering"
+ depends on SMP && !PREEMPT
+ help
+ Say Y to enable kernel lock metering, which adds overhead to SMP locks,
+ but allows you to see various statistics using the lockstat command.
+
config DEBUG_STACK_USAGE
bool "Stack utilization instrumentation"
depends on DEBUG_KERNEL
diff -Narup linux-2.6.13/arch/ppc64/lib/dec_and_lock.c linux-2.6.13-lockmeter/arch/ppc64/lib/dec_and_lock.c
--- linux-2.6.13/arch/ppc64/lib/dec_and_lock.c 2005-08-28 16:41:01.000000000 -0700
+++ linux-2.6.13-lockmeter/arch/ppc64/lib/dec_and_lock.c 2005-10-10 13:02:47.000000000 -0700
@@ -28,7 +28,13 @@
*/

#ifndef ATOMIC_DEC_AND_LOCK
+
+#ifndef CONFIG_LOCKMETER
+int atomic_dec_and_lock(atomic_t *atomic, spinlock_t *lock)
+#else
int _atomic_dec_and_lock(atomic_t *atomic, spinlock_t *lock)
+#endif /* CONFIG_LOCKMETER */
+
{
int counter;
int newcount;
@@ -51,5 +57,10 @@ int _atomic_dec_and_lock(atomic_t *atomi
return 0;
}

+#ifndef CONFIG_LOCKMETER
+EXPORT_SYMBOL(atomic_dec_and_lock);
+#else
EXPORT_SYMBOL(_atomic_dec_and_lock);
+#endif /* CONFIG_LOCKMETER */
+
#endif /* ATOMIC_DEC_AND_LOCK */
diff -Narup linux-2.6.13/include/asm-ppc64/lockmeter.h linux-2.6.13-lockmeter/include/asm-ppc64/lockmeter.h
--- linux-2.6.13/include/asm-ppc64/lockmeter.h 1969-12-31 16:00:00.000000000 -0800
+++ linux-2.6.13-lockmeter/include/asm-ppc64/lockmeter.h 2005-10-11 08:48:48.000000000 -0700
@@ -0,0 +1,110 @@
+/*
+ * Copyright (C) 1999,2000 Silicon Graphics, Inc.
+ *
+ * Written by John Hawkes (hawkes@xxxxxxx)
+ * Based on klstat.h by Jack Steiner (steiner@xxxxxxx)
+ *
+ * Modified by Ray Bryant (raybry@xxxxxxxxxx)
+ * Changes Copyright (C) 2000 IBM, Inc.
+ * Added save of index in spinlock_t to improve efficiency
+ * of "hold" time reporting for spinlocks.
+ * Added support for hold time statistics for read and write
+ * locks.
+ * Moved machine dependent code here from include/lockmeter.h.
+ *
+ * Modified by Tony Garcia (garcia1@xxxxxxxxxx)
+ * Ported to Power PC 64
+ */
+
+#ifndef _PPC64_LOCKMETER_H
+#define _PPC64_LOCKMETER_H
+
+
+#include <asm/spinlock.h>
+#include <linux/version.h>
+#include <linux/cpufreq.h>
+
+#include <asm/processor.h> /* definitions for SPRN_TBRL
+ SPRN_TBRU, mftb() */
+extern unsigned long ppc_proc_freq;
+
+#define CPU_CYCLE_FREQUENCY ppc_proc_freq
+
+#define THIS_CPU_NUMBER smp_processor_id()
+
+/*
+ * macros to cache and retrieve an index value inside of a spin lock
+ * these macros assume that there are less than 65536 simultaneous
+ * (read mode) holders of a rwlock. Not normally a problem!!
+ * we also assume that the hash table has less than 65535 entries.
+ */
+/*
+ * instrumented spinlock structure -- never used to allocate storage
+ * only used in macros below to overlay a spinlock_t
+ */
+typedef struct inst_spinlock_s {
+ volatile unsigned int lock; + unsigned int index;
+} inst_spinlock_t;
+
+#define PUT_INDEX(lock_ptr,indexv) ((inst_spinlock_t *)(lock_ptr))->index = indexv
+#define GET_INDEX(lock_ptr) ((inst_spinlock_t *)(lock_ptr))->index
+
+/*
+ * macros to cache and retrieve an index value in a read/write lock
+ * as well as the cpu where a reader busy period started
+ * we use the 2nd word (the debug word) for this, so require the
+ * debug word to be present
+ */
+/*
+ * instrumented rwlock structure -- never used to allocate storage
+ * only used in macros below to overlay a rwlock_t
+ */
+typedef struct inst_rwlock_s {
+ volatile signed int lock; + unsigned int index;
+ unsigned int cpu;
+} inst_rwlock_t;
+
+#define PUT_RWINDEX(rwlock_ptr,indexv) ((inst_rwlock_t *)(rwlock_ptr))->index = indexv
+#define GET_RWINDEX(rwlock_ptr) ((inst_rwlock_t *)(rwlock_ptr))->index
+#define PUT_RW_CPU(rwlock_ptr,cpuv) ((inst_rwlock_t *)(rwlock_ptr))->cpu = cpuv
+#define GET_RW_CPU(rwlock_ptr) ((inst_rwlock_t *)(rwlock_ptr))->cpu
+
+/*
+ * return the number of readers for a rwlock_t
+ */
+#define RWLOCK_READERS(rwlock_ptr) rwlock_readers(rwlock_ptr)
+
+/* Return number of readers */
+extern inline int rwlock_readers(rwlock_t *rwlock_ptr)
+{
+ signed int tmp = rwlock_ptr->lock;
+
+ if ( tmp > 0 )
+ return tmp;
+ else
+ return 0;
+}
+
+/*
+ * return true if rwlock is write locked
+ * (note that other lock attempts can cause the lock value to be negative)
+ */
+#define RWLOCK_IS_WRITE_LOCKED(rwlock_ptr) ((signed int)(rwlock_ptr)->lock < 0)
+#define RWLOCK_IS_READ_LOCKED(rwlock_ptr) ((signed int)(rwlock_ptr)->lock > 0 )
+
+/*Written by Carl L. to get the time base counters on ppc,
+ rplaces the Intel only call rtds*/
+static inline long get_cycles64 (void)
+{
+ unsigned long tb;
+
+ /* read the upper and lower 32 bit Time base counter */
+ tb = mfspr(SPRN_TBRU);
+ tb = (tb << 32) | mfspr(SPRN_TBRL);
+
+ return(tb);
+}
+
+#endif /* _PPC64_LOCKMETER_H */
diff -Narup linux-2.6.13/include/asm-ppc64/spinlock.h linux-2.6.13-lockmeter/include/asm-ppc64/spinlock.h
--- linux-2.6.13/include/asm-ppc64/spinlock.h 2005-08-28 16:41:01.000000000 -0700
+++ linux-2.6.13-lockmeter/include/asm-ppc64/spinlock.h 2005-10-10 14:04:25.000000000 -0700
@@ -23,6 +23,9 @@

typedef struct {
volatile unsigned int lock;
+#ifdef CONFIG_LOCKMETER
+ unsigned int lockmeter_magic;
+#endif /* CONFIG_LOCKMETER */
#ifdef CONFIG_PREEMPT
unsigned int break_lock;
#endif
@@ -30,13 +33,20 @@ typedef struct {

typedef struct {
volatile signed int lock;
+#ifdef CONFIG_LOCKMETER
+ unsigned int index;
+ unsigned int cpu;
+#endif /* CONFIG_LOCKMETER */
#ifdef CONFIG_PREEMPT
unsigned int break_lock;
#endif
} rwlock_t;

-#ifdef __KERNEL__
-#define SPIN_LOCK_UNLOCKED (spinlock_t) { 0 }
+#ifdef CONFIG_LOCKMETER
+ #define SPIN_LOCK_UNLOCKED (spinlock_t) { 0 }
+#else
+ #define SPIN_LOCK_UNLOCKED (spinlock_t) { 0 , 0}
+#endif /* CONFIG_LOCKMETER */

#define spin_is_locked(x) ((x)->lock != 0)
#define spin_lock_init(x) do { *(x) = SPIN_LOCK_UNLOCKED; } while(0)
@@ -144,7 +154,7 @@ static void __inline__ _raw_spin_lock_fl
* irq-safe write-lock, but readers can get non-irqsafe
* read-locks.
*/
-#define RW_LOCK_UNLOCKED (rwlock_t) { 0 }
+#define RW_LOCK_UNLOCKED (rwlock_t) { 0 , 0 , 0 }

#define rwlock_init(x) do { *(x) = RW_LOCK_UNLOCKED; } while(0)

@@ -157,6 +167,44 @@ static __inline__ void _raw_write_unlock
rw->lock = 0;
}

+#if defined(CONFIG_LOCKMETER) && defined(CONFIG_HAVE_DEC_LOCK)
+extern void _metered_spin_lock (spinlock_t *lock, void *caller_pc);
+extern void _metered_spin_unlock(spinlock_t *lock);
+
+/*
+ * Matches what is in arch/ppc64/lib/dec_and_lock.c, except this one is
+ * "static inline" so that the spin_lock(), if actually invoked, is charged
+ * against the real caller, not against the catch-all atomic_dec_and_lock
+ */
+static inline int _atomic_dec_and_lock(atomic_t *atomic, spinlock_t *lock)
+{
+ int counter;
+ int newcount;
+
+ for (;;) {
+ counter = atomic_read(atomic);
+ newcount = counter - 1;
+ if (!newcount)
+ break; /* do it the slow way */
+
+ newcount = cmpxchg(&atomic->counter, counter, newcount);
+ if (newcount == counter)
+ return 0;
+ }
+
+ preempt_disable();
+ _metered_spin_lock(lock, __builtin_return_address(0));
+ if (atomic_dec_and_test(atomic))
+ return 1;
+ _metered_spin_unlock(lock);
+ preempt_enable();
+
+ return 0;
+}
+
+#define ATOMIC_DEC_AND_LOCK
+#endif /* CONFIG_LOCKMETER and CONFIG_HAVE_DEC_LOCK */
+
/*
* This returns the old value in the lock + 1,
* so we got a read lock if the return value is > 0.
@@ -256,5 +304,4 @@ static void __inline__ _raw_write_lock(r
}
}

-#endif /* __KERNEL__ */
#endif /* __ASM_SPINLOCK_H */
-
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Next message: Pallipadi, Venkatesh: "RE: processor module locks up hyperthreading enabled machine"
Previous message: john stultz: "Re: [RFC][PATCH 1/12] Reduced NTP rework (part 1)"
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