linux-kernel - [PATCH 2/2] tracing, perf : add cpu hotplug trace events

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [thread-next>] [day] [month] [year] [list]

Date:	Tue, 25 Jan 2011 09:54:59 +0100
From:	Vincent Guittot <vincent.guittot@...aro.org>
To:	linux-kernel@...r.kernel.org, linux-hotplug@...r.kernel.org,
	fweisbec@...il.com, rostedt@...dmis.org, amit.kucheria@...aro.org
Subject: [PATCH 2/2] tracing, perf : add cpu hotplug trace events

Please find below a new proposal for adding trace events for cpu hotplug.
The goal is to measure the latency of each part (kernel, architecture)
and also to trace the cpu hotplug activity with other power events. I
have tested these traces events on an arm platform.

Subject: [PATCH 1/2] add cpu hotplug tracepoints

this patch adds new events for cpu hotplug tracing
 * plug/unplug sequence
 * core and architecture latency measurements

Signed-off-by: Vincent Guittot <vincent.guittot@...aro.org>
---
 kernel/cpu.c |   17 +++++++++++++++++
 1 files changed, 17 insertions(+), 0 deletions(-)

diff --git a/kernel/cpu.c b/kernel/cpu.c
index 156cc55..f04e9cf 100644
--- a/kernel/cpu.c
+++ b/kernel/cpu.c
@@ -16,6 +16,9 @@
 #include <linux/mutex.h>
 #include <linux/gfp.h>

+#define CREATE_TRACE_POINTS
+#include <trace/events/cpu_hotplug.h>
+
 #ifdef CONFIG_SMP
 /* Serializes the updates to cpu_online_mask, cpu_present_mask */
 static DEFINE_MUTEX(cpu_add_remove_lock);
@@ -200,7 +203,9 @@ static int __ref take_cpu_down(void *_param)
 	int err;

 	/* Ensure this CPU doesn't handle any more interrupts. */
+	trace_cpu_hotplug_arch_disable_start((unsigned int)(param->hcpu));
 	err = __cpu_disable();
+	trace_cpu_hotplug_arch_disable_end((unsigned int)(param->hcpu));
 	if (err < 0)
 		return err;

@@ -256,7 +261,9 @@ static int __ref _cpu_down(unsigned int cpu, int
tasks_frozen)
 		cpu_relax();

 	/* This actually kills the CPU. */
+	trace_cpu_hotplug_arch_die_start(cpu);
 	__cpu_die(cpu);
+	trace_cpu_hotplug_arch_die_end(cpu);

 	/* CPU is completely dead: tell everyone.  Too late to complain. */
 	cpu_notify_nofail(CPU_DEAD | mod, hcpu);
@@ -274,6 +281,8 @@ int __ref cpu_down(unsigned int cpu)
 {
 	int err;

+	trace_cpu_hotplug_down_start(cpu);
+
 	cpu_maps_update_begin();

 	if (cpu_hotplug_disabled) {
@@ -285,6 +294,8 @@ int __ref cpu_down(unsigned int cpu)

 out:
 	cpu_maps_update_done();
+
+	trace_cpu_hotplug_down_end(cpu);
 	return err;
 }
 EXPORT_SYMBOL(cpu_down);
@@ -310,7 +321,9 @@ static int __cpuinit _cpu_up(unsigned int cpu, int
tasks_frozen)
 	}

 	/* Arch-specific enabling code. */
+	trace_cpu_hotplug_arch_up_start(cpu);
 	ret = __cpu_up(cpu);
+	trace_cpu_hotplug_arch_up_end(cpu);
 	if (ret != 0)
 		goto out_notify;
 	BUG_ON(!cpu_online(cpu));
@@ -335,6 +348,8 @@ int __cpuinit cpu_up(unsigned int cpu)
 	pg_data_t	*pgdat;
 #endif

+	trace_cpu_hotplug_up_start(cpu);
+
 	if (!cpu_possible(cpu)) {
 		printk(KERN_ERR "can't online cpu %d because it is not "
 			"configured as may-hotadd at boot time\n", cpu);
@@ -376,6 +391,8 @@ int __cpuinit cpu_up(unsigned int cpu)

 	err = _cpu_up(cpu, 0);

+	trace_cpu_hotplug_up_end(cpu);
+
 out:
 	cpu_maps_update_done();
 	return err;
-- 
1.7.1
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/