[PATCH] - kernel profiler & spinlock_contention

Jack Steiner
2003-11-26T15:23:10Z

Profiling is more useful if addresses in spinlock_contention
were attributed to the caller of spinlock_contention.

diff -Naur linux_base/arch/ia64/kernel/head.S linux/arch/ia64/kernel/head.S
--- linux_base/arch/ia64/kernel/head.S Tue Nov 25 10:03:46 2003
+++ linux/arch/ia64/kernel/head.S Tue Nov 25 15:21:58 2003
@@ -888,6 +888,8 @@
cmp4.eq p14,p0=r30,r0
(p14) br.cond.sptk.few b6 // lock is now free, try to acquire
br.cond.sptk.few .wait
+ .global ia64_spinlock_contention_pre3_4_end // for kernprof
+ia64_spinlock_contention_pre3_4_end:
END(ia64_spinlock_contention_pre3_4)

#else

diff -Naur linux_base/arch/ia64/kernel/time.c linux/arch/ia64/kernel/time.c
--- linux_base/arch/ia64/kernel/time.c Tue Nov 25 10:03:46 2003
+++ linux/arch/ia64/kernel/time.c Tue Nov 25 10:07:21 2003
@@ -202,6 +202,9 @@
{
unsigned long ip, slot;
extern cpumask_t prof_cpu_mask;
+#ifdef CONFIG_SMP
+ extern char ia64_spinlock_contention_pre3_4[], ia64_spinlock_contention_pre3_4_end[];
+#endif

profile_hook(regs);

@@ -216,7 +219,14 @@
* bits 2 and 3 rather than bits 0 and 1.
*/
slot = ip & 3;
- ip = (ip & ~3UL) + 4*slot;
+ ip = (ip & ~3UL);
+#ifdef CONFIG_SMP
+ if (ip >= (unsigned long)ia64_spinlock_contention_pre3_4 &&
+ ip < (unsigned long)ia64_spinlock_contention_pre3_4_end)
+ ip = regs->r28;
+ else
+#endif
+ ip += 4*slot;

/*
* Only measure the CPUs specified by /proc/irq/prof_cpu_mask.
--
Thanks

Jack Steiner (steiner@sgi.com) 651-683-5302
Principal Engineer SGI - Silicon Graphics, Inc.