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authorLinus Torvalds <torvalds@linux-foundation.org>2011-03-16 04:31:30 +0300
committerLinus Torvalds <torvalds@linux-foundation.org>2011-03-16 04:31:30 +0300
commita926021cb1f8a99a275eaf6eb546102e9469dc59 (patch)
treec6d0300cd4b1a1fd658708476db4577b68b4de31 /Documentation
parent0586bed3e8563c2eb89bc7256e30ce633ae06cfb (diff)
parent5e814dd597c42daeb8d2a276e64a6ec986ad0e2a (diff)
downloadlinux-a926021cb1f8a99a275eaf6eb546102e9469dc59.tar.xz
Merge branch 'perf-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip
* 'perf-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip: (184 commits) perf probe: Clean up probe_point_lazy_walker() return value tracing: Fix irqoff selftest expanding max buffer tracing: Align 4 byte ints together in struct tracer tracing: Export trace_set_clr_event() tracing: Explain about unstable clock on resume with ring buffer warning ftrace/graph: Trace function entry before updating index ftrace: Add .ref.text as one of the safe areas to trace tracing: Adjust conditional expression latency formatting. tracing: Fix event alignment: skb:kfree_skb tracing: Fix event alignment: mce:mce_record tracing: Fix event alignment: kvm:kvm_hv_hypercall tracing: Fix event alignment: module:module_request tracing: Fix event alignment: ftrace:context_switch and ftrace:wakeup tracing: Remove lock_depth from event entry perf header: Stop using 'self' perf session: Use evlist/evsel for managing perf.data attributes perf top: Don't let events to eat up whole header line perf top: Fix events overflow in top command ring-buffer: Remove unused #include <linux/trace_irq.h> tracing: Add an 'overwrite' trace_option. ...
Diffstat (limited to 'Documentation')
-rw-r--r--Documentation/trace/ftrace-design.txt7
-rw-r--r--Documentation/trace/ftrace.txt151
-rw-r--r--Documentation/trace/kprobetrace.txt16
3 files changed, 45 insertions, 129 deletions
diff --git a/Documentation/trace/ftrace-design.txt b/Documentation/trace/ftrace-design.txt
index dc52bd442c92..79fcafc7fd64 100644
--- a/Documentation/trace/ftrace-design.txt
+++ b/Documentation/trace/ftrace-design.txt
@@ -247,6 +247,13 @@ You need very few things to get the syscalls tracing in an arch.
- Support the TIF_SYSCALL_TRACEPOINT thread flags.
- Put the trace_sys_enter() and trace_sys_exit() tracepoints calls from ptrace
in the ptrace syscalls tracing path.
+- If the system call table on this arch is more complicated than a simple array
+ of addresses of the system calls, implement an arch_syscall_addr to return
+ the address of a given system call.
+- If the symbol names of the system calls do not match the function names on
+ this arch, define ARCH_HAS_SYSCALL_MATCH_SYM_NAME in asm/ftrace.h and
+ implement arch_syscall_match_sym_name with the appropriate logic to return
+ true if the function name corresponds with the symbol name.
- Tag this arch as HAVE_SYSCALL_TRACEPOINTS.
diff --git a/Documentation/trace/ftrace.txt b/Documentation/trace/ftrace.txt
index 557c1edeccaf..1ebc24cf9a55 100644
--- a/Documentation/trace/ftrace.txt
+++ b/Documentation/trace/ftrace.txt
@@ -80,11 +80,11 @@ of ftrace. Here is a list of some of the key files:
tracers listed here can be configured by
echoing their name into current_tracer.
- tracing_enabled:
+ tracing_on:
- This sets or displays whether the current_tracer
- is activated and tracing or not. Echo 0 into this
- file to disable the tracer or 1 to enable it.
+ This sets or displays whether writing to the trace
+ ring buffer is enabled. Echo 0 into this file to disable
+ the tracer or 1 to enable it.
trace:
@@ -202,10 +202,6 @@ Here is the list of current tracers that may be configured.
to draw a graph of function calls similar to C code
source.
- "sched_switch"
-
- Traces the context switches and wakeups between tasks.
-
"irqsoff"
Traces the areas that disable interrupts and saves
@@ -273,39 +269,6 @@ format, the function name that was traced "path_put" and the
parent function that called this function "path_walk". The
timestamp is the time at which the function was entered.
-The sched_switch tracer also includes tracing of task wakeups
-and context switches.
-
- ksoftirqd/1-7 [01] 1453.070013: 7:115:R + 2916:115:S
- ksoftirqd/1-7 [01] 1453.070013: 7:115:R + 10:115:S
- ksoftirqd/1-7 [01] 1453.070013: 7:115:R ==> 10:115:R
- events/1-10 [01] 1453.070013: 10:115:S ==> 2916:115:R
- kondemand/1-2916 [01] 1453.070013: 2916:115:S ==> 7:115:R
- ksoftirqd/1-7 [01] 1453.070013: 7:115:S ==> 0:140:R
-
-Wake ups are represented by a "+" and the context switches are
-shown as "==>". The format is:
-
- Context switches:
-
- Previous task Next Task
-
- <pid>:<prio>:<state> ==> <pid>:<prio>:<state>
-
- Wake ups:
-
- Current task Task waking up
-
- <pid>:<prio>:<state> + <pid>:<prio>:<state>
-
-The prio is the internal kernel priority, which is the inverse
-of the priority that is usually displayed by user-space tools.
-Zero represents the highest priority (99). Prio 100 starts the
-"nice" priorities with 100 being equal to nice -20 and 139 being
-nice 19. The prio "140" is reserved for the idle task which is
-the lowest priority thread (pid 0).
-
-
Latency trace format
--------------------
@@ -491,78 +454,10 @@ x494] <- /root/a.out[+0x4a8] <- /lib/libc-2.7.so[+0x1e1a6]
latencies, as described in "Latency
trace format".
-sched_switch
-------------
-
-This tracer simply records schedule switches. Here is an example
-of how to use it.
-
- # echo sched_switch > current_tracer
- # echo 1 > tracing_enabled
- # sleep 1
- # echo 0 > tracing_enabled
- # cat trace
-
-# tracer: sched_switch
-#
-# TASK-PID CPU# TIMESTAMP FUNCTION
-# | | | | |
- bash-3997 [01] 240.132281: 3997:120:R + 4055:120:R
- bash-3997 [01] 240.132284: 3997:120:R ==> 4055:120:R
- sleep-4055 [01] 240.132371: 4055:120:S ==> 3997:120:R
- bash-3997 [01] 240.132454: 3997:120:R + 4055:120:S
- bash-3997 [01] 240.132457: 3997:120:R ==> 4055:120:R
- sleep-4055 [01] 240.132460: 4055:120:D ==> 3997:120:R
- bash-3997 [01] 240.132463: 3997:120:R + 4055:120:D
- bash-3997 [01] 240.132465: 3997:120:R ==> 4055:120:R
- <idle>-0 [00] 240.132589: 0:140:R + 4:115:S
- <idle>-0 [00] 240.132591: 0:140:R ==> 4:115:R
- ksoftirqd/0-4 [00] 240.132595: 4:115:S ==> 0:140:R
- <idle>-0 [00] 240.132598: 0:140:R + 4:115:S
- <idle>-0 [00] 240.132599: 0:140:R ==> 4:115:R
- ksoftirqd/0-4 [00] 240.132603: 4:115:S ==> 0:140:R
- sleep-4055 [01] 240.133058: 4055:120:S ==> 3997:120:R
- [...]
-
-
-As we have discussed previously about this format, the header
-shows the name of the trace and points to the options. The
-"FUNCTION" is a misnomer since here it represents the wake ups
-and context switches.
-
-The sched_switch file only lists the wake ups (represented with
-'+') and context switches ('==>') with the previous task or
-current task first followed by the next task or task waking up.
-The format for both of these is PID:KERNEL-PRIO:TASK-STATE.
-Remember that the KERNEL-PRIO is the inverse of the actual
-priority with zero (0) being the highest priority and the nice
-values starting at 100 (nice -20). Below is a quick chart to map
-the kernel priority to user land priorities.
-
- Kernel Space User Space
- ===============================================================
- 0(high) to 98(low) user RT priority 99(high) to 1(low)
- with SCHED_RR or SCHED_FIFO
- ---------------------------------------------------------------
- 99 sched_priority is not used in scheduling
- decisions(it must be specified as 0)
- ---------------------------------------------------------------
- 100(high) to 139(low) user nice -20(high) to 19(low)
- ---------------------------------------------------------------
- 140 idle task priority
- ---------------------------------------------------------------
-
-The task states are:
-
- R - running : wants to run, may not actually be running
- S - sleep : process is waiting to be woken up (handles signals)
- D - disk sleep (uninterruptible sleep) : process must be woken up
- (ignores signals)
- T - stopped : process suspended
- t - traced : process is being traced (with something like gdb)
- Z - zombie : process waiting to be cleaned up
- X - unknown
-
+ overwrite - This controls what happens when the trace buffer is
+ full. If "1" (default), the oldest events are
+ discarded and overwritten. If "0", then the newest
+ events are discarded.
ftrace_enabled
--------------
@@ -607,10 +502,10 @@ an example:
# echo irqsoff > current_tracer
# echo latency-format > trace_options
# echo 0 > tracing_max_latency
- # echo 1 > tracing_enabled
+ # echo 1 > tracing_on
# ls -ltr
[...]
- # echo 0 > tracing_enabled
+ # echo 0 > tracing_on
# cat trace
# tracer: irqsoff
#
@@ -715,10 +610,10 @@ is much like the irqsoff tracer.
# echo preemptoff > current_tracer
# echo latency-format > trace_options
# echo 0 > tracing_max_latency
- # echo 1 > tracing_enabled
+ # echo 1 > tracing_on
# ls -ltr
[...]
- # echo 0 > tracing_enabled
+ # echo 0 > tracing_on
# cat trace
# tracer: preemptoff
#
@@ -863,10 +758,10 @@ tracers.
# echo preemptirqsoff > current_tracer
# echo latency-format > trace_options
# echo 0 > tracing_max_latency
- # echo 1 > tracing_enabled
+ # echo 1 > tracing_on
# ls -ltr
[...]
- # echo 0 > tracing_enabled
+ # echo 0 > tracing_on
# cat trace
# tracer: preemptirqsoff
#
@@ -1026,9 +921,9 @@ Instead of performing an 'ls', we will run 'sleep 1' under
# echo wakeup > current_tracer
# echo latency-format > trace_options
# echo 0 > tracing_max_latency
- # echo 1 > tracing_enabled
+ # echo 1 > tracing_on
# chrt -f 5 sleep 1
- # echo 0 > tracing_enabled
+ # echo 0 > tracing_on
# cat trace
# tracer: wakeup
#
@@ -1140,9 +1035,9 @@ ftrace_enabled is set; otherwise this tracer is a nop.
# sysctl kernel.ftrace_enabled=1
# echo function > current_tracer
- # echo 1 > tracing_enabled
+ # echo 1 > tracing_on
# usleep 1
- # echo 0 > tracing_enabled
+ # echo 0 > tracing_on
# cat trace
# tracer: function
#
@@ -1180,7 +1075,7 @@ int trace_fd;
[...]
int main(int argc, char *argv[]) {
[...]
- trace_fd = open(tracing_file("tracing_enabled"), O_WRONLY);
+ trace_fd = open(tracing_file("tracing_on"), O_WRONLY);
[...]
if (condition_hit()) {
write(trace_fd, "0", 1);
@@ -1631,9 +1526,9 @@ If I am only interested in sys_nanosleep and hrtimer_interrupt:
# echo sys_nanosleep hrtimer_interrupt \
> set_ftrace_filter
# echo function > current_tracer
- # echo 1 > tracing_enabled
+ # echo 1 > tracing_on
# usleep 1
- # echo 0 > tracing_enabled
+ # echo 0 > tracing_on
# cat trace
# tracer: ftrace
#
@@ -1879,9 +1774,9 @@ different. The trace is live.
# echo function > current_tracer
# cat trace_pipe > /tmp/trace.out &
[1] 4153
- # echo 1 > tracing_enabled
+ # echo 1 > tracing_on
# usleep 1
- # echo 0 > tracing_enabled
+ # echo 0 > tracing_on
# cat trace
# tracer: function
#
diff --git a/Documentation/trace/kprobetrace.txt b/Documentation/trace/kprobetrace.txt
index 5f77d94598dd..6d27ab8d6e9f 100644
--- a/Documentation/trace/kprobetrace.txt
+++ b/Documentation/trace/kprobetrace.txt
@@ -42,11 +42,25 @@ Synopsis of kprobe_events
+|-offs(FETCHARG) : Fetch memory at FETCHARG +|- offs address.(**)
NAME=FETCHARG : Set NAME as the argument name of FETCHARG.
FETCHARG:TYPE : Set TYPE as the type of FETCHARG. Currently, basic types
- (u8/u16/u32/u64/s8/s16/s32/s64) and string are supported.
+ (u8/u16/u32/u64/s8/s16/s32/s64), "string" and bitfield
+ are supported.
(*) only for return probe.
(**) this is useful for fetching a field of data structures.
+Types
+-----
+Several types are supported for fetch-args. Kprobe tracer will access memory
+by given type. Prefix 's' and 'u' means those types are signed and unsigned
+respectively. Traced arguments are shown in decimal (signed) or hex (unsigned).
+String type is a special type, which fetches a "null-terminated" string from
+kernel space. This means it will fail and store NULL if the string container
+has been paged out.
+Bitfield is another special type, which takes 3 parameters, bit-width, bit-
+offset, and container-size (usually 32). The syntax is;
+
+ b<bit-width>@<bit-offset>/<container-size>
+
Per-Probe Event Filtering
-------------------------