about use wild cards for set_ftrace_filter and so on

PATCH Applied walimis 4 participants 10 messages Nov 27, 2008 – Nov 28, 2008 Documentation

Share & tools

walimis

author

2008-11-27 15:21 UTC #0 lore raw

Hi Steven and Ingo,

I encountered an issue when using ftrace.
We know that we can use wild cards to set set_ftrace_filter, but there's problem when using such as "echo h* > /debug/tracing/set_ftrace_filter". If there are files named with "h" prefix in current directory, echo "h*" will echo these files' name to set_ftrace_filter, not "h*". For example:

#cat /debug/tracing/available_filter_functions |grep ^hr |wc -l 23
#ls
#touch hraa hrdd
#ls
hraa hrdd
#echo hr* > /debug/tracing/set_ftrace_filter
#cat /debug/tracing/set_ftrace_filter

No output in /debug/tracing/set_ftrace_filter!
If we use "" to enclose wild cards, it works:

#ls
hraa hrdd
#echo "hr*" > /debug/tracing/set_ftrace_filter
#cat /debug/tracing/set_ftrace_filter |wc -l
23

This problem can lead to unexpected result if current directory has a lot of files.
I suppose that we can add some notes to document, so a patch attached.

Impact: imporve document

Signed-off-by walimis <[email protected]>

---
 Documentation/ftrace.txt |    3 +++
 1 files changed, 3 insertions(+), 0 deletions(-)

Documentation/ftrace.txt +3 -0

index de05042..9735434 100644
@@ -1251,6 +1251,9 @@ These are the only wild cards which are supported.
 
   <match>*<match> will not work.
 
+Note: you'd better to use "" to enclose wild cards, otherwise in some
+case you can't get the correct result.
+
  # echo hrtimer_* > /debug/tracing/set_ftrace_filter
 
 Produces:

Signature · 1 line

1.6.0.3

Steven Rostedt

2008-11-27 15:34 UTC #1 lore raw

Quoted 26 lines · walimis

I encountered an issue when using ftrace.
We know that we can use wild cards to set set_ftrace_filter, but there's problem when using such as "echo h* > /debug/tracing/set_ftrace_filter". If there are files named with "h" prefix in current directory, echo "h*" will echo these files' name to set_ftrace_filter, not "h*". For example:
#cat /debug/tracing/available_filter_functions |grep ^hr |wc -l 23
#ls
#touch hraa hrdd
#ls
hraa hrdd
#echo hr* > /debug/tracing/set_ftrace_filter
#cat /debug/tracing/set_ftrace_filter
No output in /debug/tracing/set_ftrace_filter!
If we use "" to enclose wild cards, it works:
#ls
hraa hrdd
#echo "hr*" > /debug/tracing/set_ftrace_filter
#cat /debug/tracing/set_ftrace_filter |wc -l
23

Quoted 3 lines

This problem can lead to unexpected result if current directory has a lot of files.
I suppose that we can add some notes to document, so a patch attached.

Using TB? It's best to inline the patch, that way I can comment on it better.

Anyway, you should fix the example. I also recommend a single quote over double, to prevent any other translation that bash might do.

The example in ftrace.txt should be:

 # echo 'hrtimer_*' > /debug/tracing/set_ftrace_filter

Thanks,

-- Steve

/me goes back to eating turkeys.

walimis

author

2008-11-27 15:51 UTC #2 lore raw

Quoted 29 lines · Steven Rostedt

Quoted 26 lines · walimis
I encountered an issue when using ftrace.
We know that we can use wild cards to set set_ftrace_filter, but there's problem when using such as "echo h* > /debug/tracing/set_ftrace_filter". If there are files named with "h" prefix in current directory, echo "h*" will echo these files' name to set_ftrace_filter, not "h*". For example:
#cat /debug/tracing/available_filter_functions |grep ^hr |wc -l 23
#ls
#touch hraa hrdd
#ls
hraa hrdd
#echo hr* > /debug/tracing/set_ftrace_filter
#cat /debug/tracing/set_ftrace_filter
No output in /debug/tracing/set_ftrace_filter!
If we use "" to enclose wild cards, it works:
#ls
hraa hrdd
#echo "hr*" > /debug/tracing/set_ftrace_filter
#cat /debug/tracing/set_ftrace_filter |wc -l
23

Quoted 6 lines

Quoted 3 lines
This problem can lead to unexpected result if current directory has a lot of files.
I suppose that we can add some notes to document, so a patch attached.
Using TB? It's best to inline the patch, that way I can comment on it better.

Using mutt, but I don't know how to inline the patch now.

Quoted 6 lines

Anyway, you should fix the example. I also recommend a single quote over double, to prevent any other translation that bash might do.
The example in ftrace.txt should be:

Quoted 8 lines

# echo 'hrtimer_*' > /debug/tracing/set_ftrace_filter
Thanks,
-- Steve
/me goes back to eating turkeys.

I only add a note, but I wonder whether enough.
If needed, I can add a example to this document.

Impact: imporve document

Signed-off-by walimis <[email protected]>

---
 Documentation/ftrace.txt |    3 +++
 1 files changed, 3 insertions(+), 0 deletions(-)

Documentation/ftrace.txt +3 -0

index de05042..9735434 100644
@@ -1251,6 +1251,9 @@ These are the only wild cards which are supported.
 
   <match>*<match> will not work.
 
+Note: you'd better to use '' to enclose wild cards, otherwise in some
+case you can't get the correct result.
+
  # echo hrtimer_* > /debug/tracing/set_ftrace_filter
 
 Produces:

Signature · 1 line

1.6.0.3

Frédéric Weisbecker

2008-11-27 15:58 UTC #3 lore raw

2008/11/27 walimis <[email protected]>:

Quoted 77 lines · Steven Rostedt

Quoted 29 lines · walimis
Quoted 27 lines
I encountered an issue when using ftrace.
We know that we can use wild cards to set set_ftrace_filter, but there's problem when using such as "echo h* > /debug/tracing/set_ftrace_filter". If there are files named with "h" prefix in current directory, echo "h*" will echo these files' name to set_ftrace_filter, not "h*". For example:
#cat /debug/tracing/available_filter_functions |grep ^hr |wc -l 23
#ls
#touch hraa hrdd
#ls
hraa hrdd
#echo hr* > /debug/tracing/set_ftrace_filter
#cat /debug/tracing/set_ftrace_filter
No output in /debug/tracing/set_ftrace_filter!
If we use "" to enclose wild cards, it works:
#ls
hraa hrdd
#echo "hr*" > /debug/tracing/set_ftrace_filter
#cat /debug/tracing/set_ftrace_filter |wc -l
23
Quoted 6 lines
Quoted 3 lines
This problem can lead to unexpected result if current directory has a lot of files.
I suppose that we can add some notes to document, so a patch attached.
Using TB? It's best to inline the patch, that way I can comment on it better.
Using mutt, but I don't know how to inline the patch now.
Quoted 6 lines
Anyway, you should fix the example. I also recommend a single quote over double, to prevent any other translation that bash might do.
The example in ftrace.txt should be:
Quoted 8 lines
# echo 'hrtimer_*' > /debug/tracing/set_ftrace_filter
Thanks,
-- Steve
/me goes back to eating turkeys.
I only add a note, but I wonder whether enough.
If needed, I can add a example to this document.
Impact: imporve document
Signed-off-by walimis <[email protected]>
---
 Documentation/ftrace.txt |    3 +++
 1 files changed, 3 insertions(+), 0 deletions(-)
Documentation/ftrace.txt +3 -1
index de05042..9735434 100644
@@ -1251,6 +1251,9 @@ These are the only wild cards which are supported.
 
  <match>*<match> will not work.
 
+Note: you'd better to use '' to enclose wild cards, otherwise in some
+case you can't get the correct result.
+
 # echo hrtimer_* > /debug/tracing/set_ftrace_filter
 
 Produces:
--

Quoted 1 line

1.6.0.3

Cc'ed Ingo.

Ingo Molnar

2008-11-27 16:21 UTC #4 lore raw

In reply to walimis

Quoted 4 lines · walimis

I only add a note, but I wonder whether enough.
If needed, I can add a example to this document.
Impact: imporve document

[ You need to slightly improve the commit log as well ;-) ]

Documentation/ftrace.txt These are the only wild cards which are supported. · line 1257

Quoted 4 lines

Documentation/ftrace.txt +3 -0

+Note: you'd better to use '' to enclose wild cards, otherwise in some
+case you can't get the correct result.
+
  # echo hrtimer_* > /debug/tracing/set_ftrace_filter

Why not fix the example too? Something like:

Review

Quoted 5 lines

(quoted diff) +4 -0

+Note: you'd better to use '' to enclose wild cards, otherwise in some
+case you can't get the correct result due to shell wildcard 
+extension:.
+
  # echo 'hrtimer_*' > /debug/tracing/set_ftrace_filter

looks good otherwise.

Ingo

walimis

author

2008-11-28 02:32 UTC #5 lore raw

PATCH 1/1 ftrace: improve document

Impact: add notice of using wild cards correctly

We know that we can use wild cards to set set_ftrace_filter, but there's problem when using such as "echo h* > /debug/tracing/set_ftrace_filter". If there are files named with "h" prefix in current directory, echo "h*" will echo these files' name to set_ftrace_filter, not "h*". For example:
$cat /debug/tracing/available_filter_functions |grep ^hr |wc -l 23
$ls
$touch hraa hrdd
$ls
hraa hrdd
$echo hr* > /debug/tracing/set_ftrace_filter
$cat /debug/tracing/set_ftrace_filter

No output in /debug/tracing/set_ftrace_filter!
If we use '' to enclose wild cards, it works:

$ls
hraa hrdd
$echo "hr*" > /debug/tracing/set_ftrace_filter
$cat /debug/tracing/set_ftrace_filter |wc -l
23

This problem can lead to unexpected result if current directory has a lot of files.

Signed-off-by walimis <[email protected]>

Reviewed-by Ingo Molnar <[email protected]>

---
 Documentation/ftrace.txt |    7 +++++--
 1 files changed, 5 insertions(+), 2 deletions(-)

Documentation/ftrace.txt +5 -2

index de05042..0012a4a 100644
@@ -1251,7 +1251,10 @@ These are the only wild cards which are supported.
 
   <match>*<match> will not work.
 
- # echo hrtimer_* > /debug/tracing/set_ftrace_filter
+Note: you'd better to use '' to enclose wild cards, otherwise in some
+cases you can't get the correct result.
+
+ # echo 'hrtimer_*' > /debug/tracing/set_ftrace_filter
 
 Produces:

@@ -1306,7 +1309,7 @@ Again, now we want to append.
  # echo sys_nanosleep > /debug/tracing/set_ftrace_filter
  # cat /debug/tracing/set_ftrace_filter
 sys_nanosleep
- # echo hrtimer_* >> /debug/tracing/set_ftrace_filter
+ # echo 'hrtimer_*' >> /debug/tracing/set_ftrace_filter
  # cat /debug/tracing/set_ftrace_filter
 hrtimer_run_queues
 hrtimer_run_pending

Signature · 1 line

1.6.0.3

Steven Rostedt

2008-11-28 03:53 UTC #6 lore raw

Re: [PATCH 1/1] ftrace: improve document

Quoted 39 lines · walimis

Impact: add notice of using wild cards correctly
We know that we can use wild cards to set set_ftrace_filter, but there's problem when using such as "echo h* > /debug/tracing/set_ftrace_filter". If there are files named with "h" prefix in current directory, echo "h*" will echo these files' name to set_ftrace_filter, not "h*". For example:
$cat /debug/tracing/available_filter_functions |grep ^hr |wc -l 23
$ls
$touch hraa hrdd
$ls
hraa hrdd
$echo hr* > /debug/tracing/set_ftrace_filter
$cat /debug/tracing/set_ftrace_filter
No output in /debug/tracing/set_ftrace_filter!
If we use '' to enclose wild cards, it works:
$ls
hraa hrdd
$echo "hr*" > /debug/tracing/set_ftrace_filter
$cat /debug/tracing/set_ftrace_filter |wc -l
23
This problem can lead to unexpected result if current directory has a lot of files.
Signed-off-by walimis <[email protected]>
Reviewed-by Ingo Molnar <[email protected]>
---
 Documentation/ftrace.txt |    7 +++++--
 1 files changed, 5 insertions(+), 2 deletions(-)
Documentation/ftrace.txt +0 -0
index de05042..0012a4a 100644

Documentation/ftrace.txt These are the only wild cards which are supported. · line 1255

Quoted 6 lines

Documentation/ftrace.txt +2 -1

@@ -1251,7 +1251,10 @@ These are the only wild cards which are supported.
 
   <match>*<match> will not work.
 
- # echo hrtimer_* > /debug/tracing/set_ftrace_filter
+Note: you'd better to use '' to enclose wild cards, otherwise in some
+cases you can't get the correct result.

The above sounds awkward, perhaps something like:

Note: It is better to use quotes to enclose the wild cards, otherwise
the shell may expand the parameters into names of files in the local directory.

-- Steve

Quoted 19 lines

Documentation/ftrace.txt +3 -1

+
+ # echo 'hrtimer_*' > /debug/tracing/set_ftrace_filter
 
 Produces:

@@ -1306,7 +1309,7 @@ Again, now we want to append.
  # echo sys_nanosleep > /debug/tracing/set_ftrace_filter
  # cat /debug/tracing/set_ftrace_filter
 sys_nanosleep
- # echo hrtimer_* >> /debug/tracing/set_ftrace_filter
+ # echo 'hrtimer_*' >> /debug/tracing/set_ftrace_filter
  # cat /debug/tracing/set_ftrace_filter
 hrtimer_run_queues
 hrtimer_run_pending

Signature · 1 line

1.6.0.3

walimis

author

2008-11-28 04:21 UTC #7 lore raw

PATCH 1/1 ftrace: improve document

Impact: add notice of using wild cards correctly

No output in /debug/tracing/set_ftrace_filter!
If we use '' to enclose wild cards, it works:

$ls
hraa hrdd
$echo "hr*" > /debug/tracing/set_ftrace_filter
$cat /debug/tracing/set_ftrace_filter |wc -l
23

This problem can lead to unexpected result if current directory has a lot of files.

Signed-off-by walimis <[email protected]>

Reviewed-by Ingo Molnar <[email protected]>

Reviewed-by Steven Rostedt <[email protected]>

---
 Documentation/ftrace.txt |    8 ++++++--
 1 files changed, 6 insertions(+), 2 deletions(-)

Documentation/ftrace.txt +6 -2

index de05042..803b131 100644
@@ -1251,7 +1251,11 @@ These are the only wild cards which are supported.
 
   <match>*<match> will not work.
 
- # echo hrtimer_* > /debug/tracing/set_ftrace_filter
+Note: It is better to use quotes to enclose the wild cards, otherwise
+  the shell may expand the parameters into names of files in the local
+  directory.
+
+ # echo 'hrtimer_*' > /debug/tracing/set_ftrace_filter
 
 Produces:

@@ -1306,7 +1310,7 @@ Again, now we want to append.
  # echo sys_nanosleep > /debug/tracing/set_ftrace_filter
  # cat /debug/tracing/set_ftrace_filter
 sys_nanosleep
- # echo hrtimer_* >> /debug/tracing/set_ftrace_filter
+ # echo 'hrtimer_*' >> /debug/tracing/set_ftrace_filter
  # cat /debug/tracing/set_ftrace_filter
 hrtimer_run_queues
 hrtimer_run_pending

Signature · 1 line

1.6.0.3

Steven Rostedt

Acked-by on v1 1/1

2008-11-28 06:56 UTC #8 lore raw

Re: [PATCH 1/1] ftrace: improve document

Quoted 4 lines · walimis

Signed-off-by walimis <[email protected]>
Reviewed-by Ingo Molnar <[email protected]>
Reviewed-by Steven Rostedt <[email protected]>

Acked-by Steven Rostedt <[email protected]>

-- Steve

Quoted 35 lines

---
 Documentation/ftrace.txt |    8 ++++++--
 1 files changed, 6 insertions(+), 2 deletions(-)

Documentation/ftrace.txt +6 -2

index de05042..803b131 100644
@@ -1251,7 +1251,11 @@ These are the only wild cards which are supported.
 
   <match>*<match> will not work.
 
- # echo hrtimer_* > /debug/tracing/set_ftrace_filter
+Note: It is better to use quotes to enclose the wild cards, otherwise
+  the shell may expand the parameters into names of files in the local
+  directory.
+
+ # echo 'hrtimer_*' > /debug/tracing/set_ftrace_filter
 
 Produces:

@@ -1306,7 +1310,7 @@ Again, now we want to append.
  # echo sys_nanosleep > /debug/tracing/set_ftrace_filter
  # cat /debug/tracing/set_ftrace_filter
 sys_nanosleep
- # echo hrtimer_* >> /debug/tracing/set_ftrace_filter
+ # echo 'hrtimer_*' >> /debug/tracing/set_ftrace_filter
  # cat /debug/tracing/set_ftrace_filter
 hrtimer_run_queues
 hrtimer_run_pending

Signature · 1 line

1.6.0.3

Ingo Molnar

Acked-by Steven Rostedt Applied

2008-11-28 12:16 UTC #9 lore raw

Re: [PATCH 1/1] ftrace: improve document

Quoted 8 lines · Steven Rostedt

Quoted 4 lines · walimis
Signed-off-by walimis <[email protected]>
Reviewed-by Ingo Molnar <[email protected]>
Reviewed-by Steven Rostedt <[email protected]>
Acked-by Steven Rostedt <[email protected]>

applied it to tip/tracing/ftrace, thanks guys! (Changed the commit log a bit, see the final commit below.)

Ingo

-------------->

Quoted 1 line

From c072c24975ec4f0ccfcb6f5c8a8040b6eb75ef8f Mon Sep 17 00:00:00 2001

From: walimis <[email protected]>
Date: Fri, 28 Nov 2008 12:21:19 +0800
Subject: [PATCH] ftrace: improve documentation

Impact: extend documentation with notice of using wild cards correctly

We know that we can use wild cards to set set_ftrace_filter, but there's problem when using them naively such as:

echo h* > /debug/tracing/set_ftrace_filter

If there are files named with "h" prefix in current directory, echo "h*" will echo these filenames to set_ftrace_filter, not the intended "h*".

For example:

  $ cat /debug/tracing/available_filter_functions |grep ^hr |wc -l
  23
  $ ls
  $ touch hraa hrdd
  $ ls
  hraa  hrdd
  $ echo hr* > /debug/tracing/set_ftrace_filter
  $ cat /debug/tracing/set_ftrace_filter

No output in /debug/tracing/set_ftrace_filter!

If we use '' to escape wild cards, it works:

  $ ls
  hraa  hrdd
  $ echo "hr*" > /debug/tracing/set_ftrace_filter
  $ cat /debug/tracing/set_ftrace_filter |wc -l
  23

This problem can lead to unexpected result if current directory has a lot of files.

Signed-off-by walimis <[email protected]>

Acked-by Steven Rostedt <[email protected]>

Signed-off-by Ingo Molnar <[email protected]>

---
 Documentation/ftrace.txt |    8 ++++++--
 1 files changed, 6 insertions(+), 2 deletions(-)

Documentation/ftrace.txt +6 -2

index de05042..803b131 100644
@@ -1251,7 +1251,11 @@ These are the only wild cards which are supported.
 
   <match>*<match> will not work.
 
- # echo hrtimer_* > /debug/tracing/set_ftrace_filter
+Note: It is better to use quotes to enclose the wild cards, otherwise
+  the shell may expand the parameters into names of files in the local
+  directory.
+
+ # echo 'hrtimer_*' > /debug/tracing/set_ftrace_filter
 
 Produces:

@@ -1306,7 +1310,7 @@ Again, now we want to append.
  # echo sys_nanosleep > /debug/tracing/set_ftrace_filter
  # cat /debug/tracing/set_ftrace_filter
 sys_nanosleep
- # echo hrtimer_* >> /debug/tracing/set_ftrace_filter
+ # echo 'hrtimer_*' >> /debug/tracing/set_ftrace_filter
  # cat /debug/tracing/set_ftrace_filter
 hrtimer_run_queues
 hrtimer_run_pending