[PATCH 0/2] [GIT PULL] tracing/ring-buffer-benchmark: mods and fixes

[PATCH 0/2] [GIT PULL] tracing/ring-buffer-benchmark: mods and fixes

[Steven Rostedt]

Ingo,

Please pull the latest tip/tracing/core tree, which can be found at:

  git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-2.6-trace.git
tip/tracing/core


Lai Jiangshan (1):
      tracing: Separate raw syscall from syscall tracer

Steven Rostedt (1):
      ring-buffer-benchmark: Add parameters to set produce/consumer priorities

----
 include/trace/events/syscalls.h      |    3 +-
 kernel/trace/ring_buffer_benchmark.c |   58 ++++++++++++++++++++++++++++++++-
 2 files changed, 58 insertions(+), 3 deletions(-)

[PATCH 1/2] [PATCH 1/2] ring-buffer-benchmark: Add parameters to set produce/consumer priorities

[Steven Rostedt]

[-- Attachment #1: 0001-ring-buffer-benchmark-Add-parameters-to-set-produce-.patch --]
[-- Type: text/plain, Size: 3512 bytes --]

From: Steven Rostedt <srostedt@redhat.com>

Running the ring-buffer-benchmark's threads at the lowest priority may
work well for keeping it in the background, but it is not appropriate
for the benchmarks.

This patch adds 4 parameters to the module:

  consumer_fifo
  consumer_nice
  producer_fifo
  producer_nice

By default the consumer and producer still run at nice +19.

If the *_fifo options are set, they will override the *_nice values.

 modprobe ring_buffer_benchmark consumer_nice=0 producer_fifo=10

The above will set the consumer thread to a nice value of 0, and
the producer thread to a RT SCHED_FIFO priority of 10.

Note, this patch also fixes a bug where calling set_user_nice on the
consumer thread would oops the kernel when the parameter "disable_reader"
is set.

Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
---
 kernel/trace/ring_buffer_benchmark.c |   58 ++++++++++++++++++++++++++++++++-
 1 files changed, 56 insertions(+), 2 deletions(-)

diff --git a/kernel/trace/ring_buffer_benchmark.c b/kernel/trace/ring_buffer_benchmark.c
index 3875d49..b2477ca 100644
--- a/kernel/trace/ring_buffer_benchmark.c
+++ b/kernel/trace/ring_buffer_benchmark.c
@@ -39,6 +39,24 @@ static int write_iteration = 50;
 module_param(write_iteration, uint, 0644);
 MODULE_PARM_DESC(write_iteration, "# of writes between timestamp readings");
 
+static int producer_nice = 19;
+static int consumer_nice = 19;
+
+static int producer_fifo = -1;
+static int consumer_fifo = -1;
+
+module_param(producer_nice, uint, 0644);
+MODULE_PARM_DESC(producer_nice, "nice prio for producer");
+
+module_param(consumer_nice, uint, 0644);
+MODULE_PARM_DESC(consumer_nice, "nice prio for consumer");
+
+module_param(producer_fifo, uint, 0644);
+MODULE_PARM_DESC(producer_fifo, "fifo prio for producer");
+
+module_param(consumer_fifo, uint, 0644);
+MODULE_PARM_DESC(consumer_fifo, "fifo prio for consumer");
+
 static int read_events;
 
 static int kill_test;
@@ -270,6 +288,27 @@ static void ring_buffer_producer(void)
 
 	if (kill_test)
 		trace_printk("ERROR!\n");
+
+	if (!disable_reader) {
+		if (consumer_fifo < 0)
+			trace_printk("Running Consumer at nice: %d\n",
+				     consumer_nice);
+		else
+			trace_printk("Running Consumer at SCHED_FIFO %d\n",
+				     consumer_fifo);
+	}
+	if (producer_fifo < 0)
+		trace_printk("Running Producer at nice: %d\n",
+			     producer_nice);
+	else
+		trace_printk("Running Producer at SCHED_FIFO %d\n",
+			     producer_fifo);
+
+	/* Let the user know that the test is running at low priority */
+	if (producer_fifo < 0 && consumer_fifo < 0 &&
+	    producer_nice == 19 && consumer_nice == 19)
+		trace_printk("WARNING!!! This test is running at lowest priority.\n");
+
 	trace_printk("Time:     %lld (usecs)\n", time);
 	trace_printk("Overruns: %lld\n", overruns);
 	if (disable_reader)
@@ -402,8 +441,23 @@ static int __init ring_buffer_benchmark_init(void)
 	/*
 	 * Run them as low-prio background tasks by default:
 	 */
-	set_user_nice(consumer, 19);
-	set_user_nice(producer, 19);
+	if (!disable_reader) {
+		if (consumer_fifo >= 0) {
+			struct sched_param param = {
+				.sched_priority = consumer_fifo
+			};
+			sched_setscheduler(consumer, SCHED_FIFO, &param);
+		} else
+			set_user_nice(consumer, consumer_nice);
+	}
+
+	if (producer_fifo >= 0) {
+		struct sched_param param = {
+			.sched_priority = consumer_fifo
+		};
+		sched_setscheduler(producer, SCHED_FIFO, &param);
+	} else
+		set_user_nice(producer, producer_nice);
 
 	return 0;
 
-- 
1.6.5

[PATCH 2/2] [PATCH 2/2] tracing: Separate raw syscall from syscall tracer

[Steven Rostedt]

[-- Attachment #1: 0002-tracing-Separate-raw-syscall-from-syscall-tracer.patch --]
[-- Type: text/plain, Size: 2416 bytes --]

From: Lai Jiangshan <laijs@cn.fujitsu.com>

The current syscall tracer mixes raw syscalls and real syscalls.

echo 1 > events/syscalls/enable
And we get these from the output:

(XXXX insteads "            grep-20914 [001] 588211.446347" .. etc)

XXXX: sys_read(fd: 3, buf: 80609a8, count: 7000)
XXXX: sys_enter: NR 3 (3, 80609a8, 7000, a, 1000, bfce8ef8)
XXXX: sys_read -> 0x138
XXXX: sys_exit: NR 3 = 312
XXXX: sys_read(fd: 3, buf: 8060ae0, count: 7000)
XXXX: sys_enter: NR 3 (3, 8060ae0, 7000, a, 1000, bfce8ef8)
XXXX: sys_read -> 0x138
XXXX: sys_exit: NR 3 = 312

There are 2 drawbacks here.
A) two almost identical records are saved in ringbuffer
   when a syscall enters or exits. (4 records for every syscall)
   This wastes precious space in the ring buffer.
B) the lines including "sys_enter/sys_exit" produces
   hardly any useful information for the output (no labels).

The user can use this method to prevent these drawbacks:
echo 1 > events/syscalls/enable
echo 0 > events/syscalls/sys_enter/enable
echo 0 > events/syscalls/sys_exit/enable

But this is not user friendly. So we separate raw syscall
from syscall tracer.

After this fix applied:
syscall tracer's output (echo 1 > events/syscalls/enable):

XXXX: sys_read(fd: 3, buf: bfe87d88, count: 200)
XXXX: sys_read -> 0x200
XXXX: sys_fstat64(fd: 3, statbuf: bfe87c98)
XXXX: sys_fstat64 -> 0x0
XXXX: sys_close(fd: 3)

raw syscall tracer's output (echo 1 > events/raw_syscalls/enable):

XXXX: sys_enter: NR 175 (0, bf92bf18, bf92bf98, 8, b748cff4, bf92bef8)
XXXX: sys_exit: NR 175 = 0
XXXX: sys_enter: NR 175 (2, bf92bf98, 0, 8, b748cff4, bf92bef8)
XXXX: sys_exit: NR 175 = 0
XXXX: sys_enter: NR 3 (9, bf927f9c, 4000, b77e2518, b77dce60, bf92bff8)

Signed-off-by: Lai Jiangshan <laijs@cn.fujitsu.com>
LKML-Reference: <4AEFC37C.5080609@cn.fujitsu.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
---
 include/trace/events/syscalls.h |    3 ++-
 1 files changed, 2 insertions(+), 1 deletions(-)

diff --git a/include/trace/events/syscalls.h b/include/trace/events/syscalls.h
index 397dff2..fb726ac 100644
--- a/include/trace/events/syscalls.h
+++ b/include/trace/events/syscalls.h
@@ -1,5 +1,6 @@
 #undef TRACE_SYSTEM
-#define TRACE_SYSTEM syscalls
+#define TRACE_SYSTEM raw_syscalls
+#define TRACE_INCLUDE_FILE syscalls
 
 #if !defined(_TRACE_EVENTS_SYSCALLS_H) || defined(TRACE_HEADER_MULTI_READ)
 #define _TRACE_EVENTS_SYSCALLS_H
-- 
1.6.5