Re: [PATCH] Scheduler Profiling - Use Immediate Values

Randy Dunlap
2007-09-06T20:57:44Z

On Thu, 6 Sep 2007 16:05:37 -0400 Mathieu Desnoyers wrote:

> Scheduler Profiling - Use Immediate Values
>
> Use immediate values with lower d-cache hit in optimized version as a
> condition for scheduler profiling call.
>
> Depends on the Immediate values patches, applies to 2.6.23-rc4-mm1.
>
> Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@polymtl.ca>
> ---
> drivers/kvm/svm.c | 2 +-
> drivers/kvm/vmx.c | 2 +-
> include/linux/profile.h | 10 ++++------
> kernel/profile.c | 38 ++++++++++++++++++++++++++------------
> kernel/sched.c | 3 ++-
> 5 files changed, 34 insertions(+), 21 deletions(-)
>
> Index: linux-2.6-lttng/kernel/profile.c
> ===================================================================
> --- linux-2.6-lttng.orig/kernel/profile.c 2007-09-04 11:53:23.000000000 -0400
> +++ linux-2.6-lttng/kernel/profile.c 2007-09-04 12:12:16.000000000 -0400
> @@ -42,9 +42,6 @@ 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);
> -
> static cpumask_t prof_cpu_mask = CPU_MASK_ALL;
> #ifdef CONFIG_SMP
> static DEFINE_PER_CPU(struct profile_hit *[2], cpu_profile_hits);
> @@ -52,6 +49,14 @@ static DEFINE_PER_CPU(int, cpu_profile_f
> static DEFINE_MUTEX(profile_flip_mutex);
> #endif /* CONFIG_SMP */
>
> +/* Immediate values */
> +immediate_char_t sleep_profiling __read_mostly,
> + sched_profiling __read_mostly,
> + kvm_profiling __read_mostly,
> + cpu_profiling __read_mostly;
> +EXPORT_SYMBOL_GPL(kvm_profiling);
> +EXPORT_SYMBOL_GPL(cpu_profiling);
> +
> static int __init profile_setup(char * str)
> {
> static char __initdata schedstr[] = "schedule";
> @@ -60,7 +65,7 @@ static int __init profile_setup(char * s
> int par;
>
> if (!strncmp(str, sleepstr, strlen(sleepstr))) {
> - prof_on = SLEEP_PROFILING;
> + immediate_set_early(&sleep_profiling, 1);

These are booleans, eh? so one could use , true);

etc.

> if (str[strlen(sleepstr)] == ',')
> str += strlen(sleepstr) + 1;
> if (get_option(&str, &par))
> @@ -99,7 +104,10 @@ __setup("profile=", profile_setup);
>
> void __init profile_init(void)
> {
> - if (!prof_on)
> + if (!_immediate_read(&sleep_profiling) &&
> + !_immediate_read(&sched_profiling) &&
> + !_immediate_read(&kvm_profiling) &&
> + !_immediate_read(&cpu_profiling))

Looks like this (in multiple places) needs to use prof_on, where
prof_on is set earlier as the logical 'or' of all (4 now, could be more)
profiling flags.
Or below, sometimes you just check prof_buffer. Is that sufficient
here also?

> return;
>
> /* only text is profiled */
> @@ -288,7 +296,7 @@ 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;
> @@ -398,7 +406,7 @@ 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)]);
> @@ -555,7 +563,10 @@ static int __init create_hash_tables(voi
> }
> return 0;
> out_cleanup:
> - prof_on = 0;
> + immediate_set_early(&sleep_profiling, 0);
> + immediate_set_early(&sched_profiling, 0);
> + immediate_set_early(&kvm_profiling, 0);
> + immediate_set_early(&cpu_profiling, 0);
> smp_mb();
> on_each_cpu(profile_nop, NULL, 0, 1);
> for_each_online_cpu(cpu) {
> @@ -582,7 +593,10 @@ static int __init create_proc_profile(vo
> {
> struct proc_dir_entry *entry;
>
> - if (!prof_on)
> + if (!_immediate_read(&sleep_profiling) &&
> + !_immediate_read(&sched_profiling) &&
> + !_immediate_read(&kvm_profiling) &&
> + !_immediate_read(&cpu_profiling))
> return 0;
> if (create_hash_tables())
> return -1;

---
~Randy
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