From: Colin Cross <ccr...@android.com>
Below is a patch from android kernel that maintains a histogram of
suspend times. Please review and provide feedback.
Prints the time spent in suspend in the kernel log, and keeps statistics
on the time spent in suspend in /sys/kernel/debug/suspend_time
Cc: Android Kernel Team <kernel-t...@android.com>
Cc: Colin Cross <ccr...@android.com>
Cc: Todd Poynor <toddpoy...@google.com>
Cc: San Mehat <s...@google.com>
Cc: Benoit Goby <ben...@android.com>
Cc: John Stultz <john.stu...@linaro.org>
Cc: Pavel Machek <pa...@ucw.cz>
Cc: Rafael J. Wysocki <r...@sisk.pl>
Cc: Len Brown <len.br...@intel.com>
Signed-off-by: Colin Cross <ccr...@android.com>
Signed-off-by: Todd Poynor <toddpoy...@google.com>
[zoran.marko...@linaro.org: Re-formatted suspend time table to better fit
expected values, tweaked commit message]
Signed-off-by: Zoran Markovic <zoran.marko...@linaro.org>
---
kernel/power/Kconfig | 7 +++
kernel/power/Makefile | 1 +
kernel/power/suspend_time.c | 111 +++++++++++++++++++++++++++++++++++++++++++
3 files changed, 119 insertions(+)
create mode 100644 kernel/power/suspend_time.c
diff --git a/kernel/power/Kconfig b/kernel/power/Kconfig
index 5dfdc9e..edc8bdd 100644
--- a/kernel/power/Kconfig
+++ b/kernel/power/Kconfig
@@ -274,3 +274,10 @@ config PM_GENERIC_DOMAINS_RUNTIME
config CPU_PM
bool
depends on SUSPEND || CPU_IDLE
+
+config SUSPEND_TIME
+ bool "Log time spent in suspend"
+ ---help---
+ Prints the time spent in suspend in the kernel log, and
+ keeps statistics on the time spent in suspend in
+ /sys/kernel/debug/suspend_time
diff --git a/kernel/power/Makefile b/kernel/power/Makefile
index 29472bf..578e20e 100644
--- a/kernel/power/Makefile
+++ b/kernel/power/Makefile
@@ -11,5 +11,6 @@ obj-$(CONFIG_HIBERNATION) += hibernate.o snapshot.o
swap.o user.o \
block_io.o
obj-$(CONFIG_PM_AUTOSLEEP) += autosleep.o
obj-$(CONFIG_PM_WAKELOCKS) += wakelock.o
+obj-$(CONFIG_SUSPEND_TIME) += suspend_time.o
obj-$(CONFIG_MAGIC_SYSRQ) += poweroff.o
diff --git a/kernel/power/suspend_time.c b/kernel/power/suspend_time.c
new file mode 100644
index 0000000..a613ede
--- /dev/null
+++ b/kernel/power/suspend_time.c
@@ -0,0 +1,111 @@
+/*
+ * debugfs file to track time spent in suspend
+ *
+ * Copyright (c) 2011, Google, Inc.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
+ * more details.
+ */
+
+#include <linux/debugfs.h>
+#include <linux/err.h>
+#include <linux/init.h>
+#include <linux/kernel.h>
+#include <linux/seq_file.h>
+#include <linux/syscore_ops.h>
+#include <linux/time.h>
+
+static struct timespec suspend_time_before;
+static unsigned int time_in_suspend_bins[32];
+
+#ifdef CONFIG_DEBUG_FS
+static int suspend_time_debug_show(struct seq_file *s, void *data)
+{
+ unsigned int bin;
+ seq_printf(s, " time (secs) count\n");
+ seq_printf(s, "------------------------------\n");
+ for (bin = 0; bin < 32; bin++) {
+ if (time_in_suspend_bins[bin] == 0)
+ continue;
+ seq_printf(s, "%10u - %-10u %4u\n",
+ bin ? 1 << (bin - 1) : 0, 1 << bin,
+ time_in_suspend_bins[bin]);
+ }
+ return 0;
+}
+
+static int suspend_time_debug_open(struct inode *inode, struct file *file)
+{
+ return single_open(file, suspend_time_debug_show, NULL);
+}
+
+static const struct file_operations suspend_time_debug_fops = {
+ .open = suspend_time_debug_open,
+ .read = seq_read,
+ .llseek = seq_lseek,
+ .release = single_release,
+};
+
+static int __init suspend_time_debug_init(void)
+{
+ struct dentry *d;
+
+ d = debugfs_create_file("suspend_time", 0444, NULL, NULL,
+ &suspend_time_debug_fops);
+ if (!d) {
+ pr_err("Failed to create suspend_time debug file\n");
+ return -ENOMEM;
+ }
+
+ return 0;
+}
+
+late_initcall(suspend_time_debug_init);
+#endif
+
+static int suspend_time_syscore_suspend(void)
+{
+ read_persistent_clock(&suspend_time_before);
+
+ return 0;
+}
+
+static void suspend_time_syscore_resume(void)
+{
+ struct timespec after;
+
+ read_persistent_clock(&after);
+
+ after = timespec_sub(after, suspend_time_before);
+
+ time_in_suspend_bins[fls(after.tv_sec)]++;
+
+ pr_info("Suspended for %lu.%03lu seconds\n", after.tv_sec,
+ after.tv_nsec / NSEC_PER_MSEC);
+}
+
+static struct syscore_ops suspend_time_syscore_ops = {
+ .suspend = suspend_time_syscore_suspend,
+ .resume = suspend_time_syscore_resume,
+};
+
+static int suspend_time_syscore_init(void)
+{
+ register_syscore_ops(&suspend_time_syscore_ops);
+
+ return 0;
+}
+
+static void suspend_time_syscore_exit(void)
+{
+ unregister_syscore_ops(&suspend_time_syscore_ops);
+}
+module_init(suspend_time_syscore_init);
+module_exit(suspend_time_syscore_exit);
--
1.7.9.5
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