[patch 8/8] Scheduler Profiling - Use Immediate Values

Mathieu Desnoyers
2007-11-13T19:01:16Z

[-- Attachment #1: profiling-use-immediate-values.patch --]
[-- Type: text/plain, Size: 5769 bytes --]

Use immediate values with lower d-cache hit in optimized version as a
condition for scheduler profiling call.

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@polymtl.ca>
---
drivers/kvm/kvm_main.c | 3 ++-
include/linux/profile.h | 5 +++--
kernel/profile.c | 22 +++++++++++-----------
kernel/sched_fair.c | 6 +-----
4 files changed, 17 insertions(+), 19 deletions(-)

Index: linux-2.6-lttng/kernel/profile.c
===================================================================
--- linux-2.6-lttng.orig/kernel/profile.c 2007-11-13 09:48:36.000000000 -0500
+++ linux-2.6-lttng/kernel/profile.c 2007-11-13 09:48:37.000000000 -0500
@@ -42,8 +42,8 @@ static int (*timer_hook)(struct pt_regs
static atomic_t *prof_buffer;
static unsigned long prof_len, prof_shift;

-int prof_on __read_mostly;
-EXPORT_SYMBOL_GPL(prof_on);
+DEFINE_IMMEDIATE(char, prof_on) __read_mostly;
+EXPORT_IMMEDIATE_SYMBOL_GPL(prof_on);

static cpumask_t prof_cpu_mask = CPU_MASK_ALL;
#ifdef CONFIG_SMP
@@ -61,7 +61,7 @@ static int __init profile_setup(char * s

if (!strncmp(str, sleepstr, strlen(sleepstr))) {
#ifdef CONFIG_SCHEDSTATS
- prof_on = SLEEP_PROFILING;
+ immediate_set(prof_on, SLEEP_PROFILING);
if (str[strlen(sleepstr)] == ',')
str += strlen(sleepstr) + 1;
if (get_option(&str, &par))
@@ -74,7 +74,7 @@ static int __init profile_setup(char * s
"kernel sleep profiling requires CONFIG_SCHEDSTATS\n");
#endif /* CONFIG_SCHEDSTATS */
} else if (!strncmp(str, schedstr, strlen(schedstr))) {
- prof_on = SCHED_PROFILING;
+ immediate_set(prof_on, SCHED_PROFILING);
if (str[strlen(schedstr)] == ',')
str += strlen(schedstr) + 1;
if (get_option(&str, &par))
@@ -83,7 +83,7 @@ static int __init profile_setup(char * s
"kernel schedule profiling enabled (shift: %ld)\n",
prof_shift);
} else if (!strncmp(str, kvmstr, strlen(kvmstr))) {
- prof_on = KVM_PROFILING;
+ immediate_set(prof_on, KVM_PROFILING);
if (str[strlen(kvmstr)] == ',')
str += strlen(kvmstr) + 1;
if (get_option(&str, &par))
@@ -93,7 +93,7 @@ static int __init profile_setup(char * s
prof_shift);
} else if (get_option(&str, &par)) {
prof_shift = par;
- prof_on = CPU_PROFILING;
+ immediate_set(prof_on, CPU_PROFILING);
printk(KERN_INFO "kernel profiling enabled (shift: %ld)\n",
prof_shift);
}
@@ -104,7 +104,7 @@ __setup("profile=", profile_setup);

void __init profile_init(void)
{
- if (!prof_on)
+ if (!_immediate_read(prof_on))
return;

/* only text is profiled */
@@ -293,7 +293,7 @@ void profile_hits(int type, void *__pc,
int i, j, cpu;
struct profile_hit *hits;

- if (prof_on != type || !prof_buffer)
+ if (!prof_buffer)
return;
pc = min((pc - (unsigned long)_stext) >> prof_shift, prof_len - 1);
i = primary = (pc & (NR_PROFILE_GRP - 1)) << PROFILE_GRPSHIFT;
@@ -403,7 +403,7 @@ void profile_hits(int type, void *__pc,
{
unsigned long pc;

- if (prof_on != type || !prof_buffer)
+ if (!prof_buffer)
return;
pc = ((unsigned long)__pc - (unsigned long)_stext) >> prof_shift;
atomic_add(nr_hits, &prof_buffer[min(pc, prof_len - 1)]);
@@ -560,7 +560,7 @@ static int __init create_hash_tables(voi
}
return 0;
out_cleanup:
- prof_on = 0;
+ immediate_set(prof_on, 0);
smp_mb();
on_each_cpu(profile_nop, NULL, 0, 1);
for_each_online_cpu(cpu) {
@@ -587,7 +587,7 @@ static int __init create_proc_profile(vo
{
struct proc_dir_entry *entry;

- if (!prof_on)
+ if (!_immediate_read(prof_on))
return 0;
if (create_hash_tables())
return -1;
Index: linux-2.6-lttng/include/linux/profile.h
===================================================================
--- linux-2.6-lttng.orig/include/linux/profile.h 2007-11-13 09:48:36.000000000 -0500
+++ linux-2.6-lttng/include/linux/profile.h 2007-11-13 09:48:37.000000000 -0500
@@ -7,10 +7,11 @@
#include <linux/init.h>
#include <linux/cpumask.h>
#include <linux/cache.h>
+#include <linux/immediate.h>

#include <asm/errno.h>

-extern int prof_on __read_mostly;
+DECLARE_IMMEDIATE(char, prof_on) __read_mostly;

#define CPU_PROFILING 1
#define SCHED_PROFILING 2
@@ -38,7 +39,7 @@ static inline void profile_hit(int type,
/*
* Speedup for the common (no profiling enabled) case:
*/
- if (unlikely(prof_on == type))
+ if (unlikely(immediate_read(prof_on) == type))
profile_hits(type, ip, 1);
}

Index: linux-2.6-lttng/drivers/kvm/kvm_main.c
===================================================================
--- linux-2.6-lttng.orig/drivers/kvm/kvm_main.c 2007-11-13 09:48:36.000000000 -0500
+++ linux-2.6-lttng/drivers/kvm/kvm_main.c 2007-11-13 09:48:37.000000000 -0500
@@ -2054,7 +2054,8 @@ again:
/*
* Profile KVM exit RIPs:
*/
- if (unlikely(prof_on == KVM_PROFILING)) {
+
+ if (unlikely(immediate_read(prof_on) == KVM_PROFILING)) {
kvm_x86_ops->cache_regs(vcpu);
profile_hit(KVM_PROFILING, (void *)vcpu->rip);
}
Index: linux-2.6-lttng/kernel/sched_fair.c
===================================================================
--- linux-2.6-lttng.orig/kernel/sched_fair.c 2007-11-13 09:48:36.000000000 -0500
+++ linux-2.6-lttng/kernel/sched_fair.c 2007-11-13 09:48:37.000000000 -0500
@@ -455,12 +455,8 @@ static void enqueue_sleeper(struct cfs_r
* get a milliseconds-range estimation of the amount of
* time that the task spent sleeping:
*/
- if (unlikely(prof_on == SLEEP_PROFILING)) {
- struct task_struct *tsk = task_of(se);
-
- profile_hits(SLEEP_PROFILING, (void *)get_wchan(tsk),
+ profile_hits(SLEEP_PROFILING, (void *)get_wchan(task_of(se)),
delta >> 20);
- }
}
#endif
}