Not to long ago preempt_max_latency was microseconds, and someplace
along the way it turned into cycles. That's a bit unintuitive, so I
converted it back to microseconds.
Signed-Off-By: Daniel Walker <[email protected]>
---
include/linux/clocksource.h | 12 ++++++++++--
kernel/latency_trace.c | 36 +++++++++++++++++++++++++++++++++++-
kernel/sysctl.c | 12 ++++++------
3 files changed, 51 insertions(+), 9 deletions(-)
Index: linux-2.6.23/include/linux/clocksource.h
===================================================================
--- linux-2.6.23.orig/include/linux/clocksource.h
+++ linux-2.6.23/include/linux/clocksource.h
@@ -21,10 +21,18 @@
typedef u64 cycle_t;
struct clocksource;
-extern unsigned long preempt_max_latency;
-extern unsigned long preempt_thresh;
+extern unsigned long preempt_max_latency_us;
+extern unsigned long preempt_thresh_us;
extern unsigned long preempt_mark_thresh;
+struct ctl_table;
+struct file;
+extern int proc_preempt_max_latency(struct ctl_table *table, int write,
+ struct file *file, void __user *buffer,
+ size_t *length, loff_t *ppos);
+extern int proc_preempt_threshold(struct ctl_table *table, int write,
+ struct file *file, void __user *buffer,
+ size_t *length, loff_t *ppos);
/**
* struct clocksource - hardware abstraction for a free running counter
* Provides mostly state-free accessors to the underlying hardware.
Index: linux-2.6.23/kernel/latency_trace.c
===================================================================
--- linux-2.6.23.orig/kernel/latency_trace.c
+++ linux-2.6.23/kernel/latency_trace.c
@@ -27,6 +27,7 @@
#include <asm/asm-offsets.h>
#include <asm/rtc.h>
#include <linux/stacktrace.h>
+#include <linux/sysctl.h>
#ifndef DEFINE_RAW_SPINLOCK
# define DEFINE_RAW_SPINLOCK DEFINE_SPINLOCK
@@ -38,7 +39,7 @@
int trace_use_raw_cycles = 0;
-#ifdef CONFIG_EVENT_TRACE
+#if defined(CONFIG_LATENCY_TIMING) || defined(CONFIG_EVENT_TRACE)
/*
* Convert raw cycles to usecs.
* Note: this is not the 'clocksource cycles' value, it's the raw
@@ -161,11 +162,14 @@ enum trace_flag_type
*/
#ifdef CONFIG_LATENCY_HIST
unsigned long preempt_max_latency = (cycle_t)0UL;
+unsigned long preempt_max_latency_us = (cycle_t)0UL;
#else
unsigned long preempt_max_latency = (cycle_t)ULONG_MAX;
+unsigned long preempt_max_latency_us = (cycle_t)ULONG_MAX;
#endif
unsigned long preempt_thresh;
+unsigned long preempt_thresh_us;
/*
* Should this new latency be reported/recorded?
@@ -1713,6 +1717,7 @@ static int setup_preempt_thresh(char *s)
get_option(&s, &thresh);
if (thresh > 0) {
preempt_thresh = usecs_to_cycles(thresh);
+ preempt_thresh_us = thresh;
printk("Preemption threshold = %u us\n", thresh);
}
return 1;
@@ -2806,3 +2811,32 @@ void __init init_tracer(void)
total_size);
}
#endif
+
+#ifdef CONFIG_LATENCY_TIMING
+
+int proc_preempt_max_latency(struct ctl_table *table, int write,
+ struct file *file, void __user *buffer,
+ size_t *length, loff_t *ppos)
+{
+ preempt_max_latency_us = cycles_to_us(preempt_max_latency);
+
+ proc_doulongvec_minmax(table, write, file, buffer, length, ppos);
+
+ preempt_max_latency = usecs_to_cycles(preempt_max_latency_us);
+
+ return 0;
+}
+
+int proc_preempt_threshold(struct ctl_table *table, int write,
+ struct file *file, void __user *buffer,
+ size_t *length, loff_t *ppos)
+{
+ preempt_thresh_us = cycles_to_us(preempt_thresh);
+
+ proc_doulongvec_minmax(table, write, file, buffer, length, ppos);
+
+ preempt_thresh = usecs_to_cycles(preempt_thresh_us);
+
+ return 0;
+}
+#endif
Index: linux-2.6.23/kernel/sysctl.c
===================================================================
--- linux-2.6.23.orig/kernel/sysctl.c
+++ linux-2.6.23/kernel/sysctl.c
@@ -418,18 +418,18 @@ static struct ctl_table kern_table[] = {
{
.ctl_name = CTL_UNNUMBERED,
.procname = "preempt_max_latency",
- .data = &preempt_max_latency,
- .maxlen = sizeof(preempt_max_latency),
+ .data = &preempt_max_latency_us,
+ .maxlen = sizeof(preempt_max_latency_us),
.mode = 0644,
- .proc_handler = &proc_doulongvec_minmax,
+ .proc_handler = &proc_preempt_max_latency,
},
{
.ctl_name = CTL_UNNUMBERED,
.procname = "preempt_thresh",
- .data = &preempt_thresh,
- .maxlen = sizeof(preempt_thresh),
+ .data = &preempt_thresh_us,
+ .maxlen = sizeof(preempt_thresh_us),
.mode = 0644,
- .proc_handler = &proc_doulongvec_minmax,
+ .proc_handler = &proc_preempt_threshold,
},
#endif
#ifdef CONFIG_EVENT_TRACE
--
--