[RFC PATCH 29/30 v3] make varaible size buffers for traces

Steven Rostedt
2008-01-15T20:53:12Z

[-- Attachment #1: trace-variable-buffer-size.patch --]
[-- Type: text/plain, Size: 5730 bytes --]

Each trace now can have the size of its trace entries modified
through command line arguments.

trace_fn_entries - function trace entries (default 65536)
trace_irq_entries - irq off trace entries (default 512)
trace_ctx_entries - schedule switch entries (default 16384)

Signed-off-by: Steven Rostedt <srostedt@redhat.com>
---
lib/tracing/trace_function.c | 14 ++++++++++++--
lib/tracing/trace_irqsoff.c | 14 ++++++++++++--
lib/tracing/trace_sched_switch.c | 14 ++++++++++++--
lib/tracing/tracer.h | 1 -
4 files changed, 36 insertions(+), 7 deletions(-)

Index: linux-compile.git/lib/tracing/trace_function.c
===================================================================
--- linux-compile.git.orig/lib/tracing/trace_function.c 2008-01-15 15:13:59.000000000 -0500
+++ linux-compile.git/lib/tracing/trace_function.c 2008-01-15 15:15:00.000000000 -0500
@@ -18,6 +18,16 @@
static struct tracing_trace function_trace __read_mostly;
static DEFINE_PER_CPU(struct tracing_trace_cpu, function_trace_cpu);
static int trace_enabled __read_mostly;
+static unsigned long trace_nr_entries = (65536UL);
+
+static int __init set_nr_entries(char *str)
+{
+ if (!str)
+ return 0;
+ trace_nr_entries = simple_strtoul(str, &str, 0);
+ return 1;
+}
+__setup("trace_fn_entries=", set_nr_entries);

static notrace void function_trace_reset(struct tracing_trace *tr)
{
@@ -132,7 +142,7 @@ static void function_trace_close(struct

__init static int function_trace_alloc_buffers(void)
{
- const int order = page_order(TRACING_NR_ENTRIES * TRACING_ENTRY_SIZE);
+ const int order = page_order(trace_nr_entries * TRACING_ENTRY_SIZE);
const unsigned long size = (1UL << order) << PAGE_SHIFT;
struct tracing_entry *array;
int i;
@@ -156,7 +166,7 @@ __init static int function_trace_alloc_b
function_trace.entries = size / TRACING_ENTRY_SIZE;

pr_info("function tracer: %ld bytes allocated for %ld",
- size, TRACING_NR_ENTRIES);
+ size, trace_nr_entries);
pr_info(" entries of %ld bytes\n", (long)TRACING_ENTRY_SIZE);
pr_info(" actual entries %ld\n", function_trace.entries);

Index: linux-compile.git/lib/tracing/trace_irqsoff.c
===================================================================
--- linux-compile.git.orig/lib/tracing/trace_irqsoff.c 2008-01-15 15:13:59.000000000 -0500
+++ linux-compile.git/lib/tracing/trace_irqsoff.c 2008-01-15 15:15:00.000000000 -0500
@@ -25,6 +25,16 @@ static unsigned long preempt_max_latency
static unsigned long preempt_thresh;
static __cacheline_aligned_in_smp DEFINE_MUTEX(max_mutex);
static int trace_enabled __read_mostly;
+static unsigned long trace_nr_entries = (512UL);
+
+static int __init set_nr_entries(char *str)
+{
+ if (!str)
+ return 0;
+ trace_nr_entries = simple_strtoul(str, &str, 0);
+ return 1;
+}
+__setup("trace_irq_entries=", set_nr_entries);

/*
* max trace is switched with this buffer.
@@ -497,7 +507,7 @@ static void notrace irqsoff_trace_close(

__init static int trace_irqsoff_alloc_buffers(void)
{
- const int order = page_order(TRACING_NR_ENTRIES * TRACING_ENTRY_SIZE);
+ const int order = page_order(trace_nr_entries * TRACING_ENTRY_SIZE);
const unsigned long size = (1UL << order) << PAGE_SHIFT;
struct tracing_entry *array;
int i;
@@ -535,7 +545,7 @@ __init static int trace_irqsoff_alloc_bu
max_tr.stop = irqsoff_stop;

pr_info("irqs off tracer: %ld bytes allocated for %ld",
- size, TRACING_NR_ENTRIES);
+ size, trace_nr_entries);
pr_info(" entries of %d bytes\n", (int)TRACING_ENTRY_SIZE);
pr_info(" actual entries %ld\n", irqsoff_trace.entries);

Index: linux-compile.git/lib/tracing/tracer.h
===================================================================
--- linux-compile.git.orig/lib/tracing/tracer.h 2008-01-15 15:13:59.000000000 -0500
+++ linux-compile.git/lib/tracing/tracer.h 2008-01-15 15:15:00.000000000 -0500
@@ -76,7 +76,6 @@ struct tracing_iterator {
};

#define TRACING_ENTRY_SIZE sizeof(struct tracing_entry)
-#define TRACING_NR_ENTRIES (65536UL)

void notrace tracing_reset(struct tracing_trace_cpu *data);
int tracing_open_generic(struct inode *inode, struct file *filp);
Index: linux-compile.git/lib/tracing/trace_sched_switch.c
===================================================================
--- linux-compile.git.orig/lib/tracing/trace_sched_switch.c 2008-01-15 15:13:59.000000000 -0500
+++ linux-compile.git/lib/tracing/trace_sched_switch.c 2008-01-15 15:15:00.000000000 -0500
@@ -18,6 +18,16 @@ static struct tracing_trace sched_switch
static DEFINE_PER_CPU(struct tracing_trace_cpu, sched_switch_trace_cpu);

static int trace_enabled __read_mostly;
+static unsigned long trace_nr_entries = (16384UL);
+
+static int __init set_nr_entries(char *str)
+{
+ if (!str)
+ return 0;
+ trace_nr_entries = simple_strtoul(str, &str, 0);
+ return 1;
+}
+__setup("trace_ctx_entries=", set_nr_entries);

static notrace void sched_switch_callback(const struct marker *mdata,
void *private_data,
@@ -144,7 +154,7 @@ static void sched_switch_trace_close(str

__init static int sched_switch_trace_alloc_buffers(void)
{
- const int order = page_order(TRACING_NR_ENTRIES * TRACING_ENTRY_SIZE);
+ const int order = page_order(trace_nr_entries * TRACING_ENTRY_SIZE);
const unsigned long size = (1UL << order) << PAGE_SHIFT;
struct tracing_entry *array;
int ret;
@@ -170,7 +180,7 @@ __init static int sched_switch_trace_all
sched_switch_trace.entries = size / TRACING_ENTRY_SIZE;

pr_info("sched_switch tracer: %ld bytes allocated for %ld",
- size, TRACING_NR_ENTRIES);
+ size, trace_nr_entries);
pr_info(" entries of %ld bytes\n", (long)TRACING_ENTRY_SIZE);
pr_info(" actual entries %ld\n", sched_switch_trace.entries);

--