[PATCH 1/2] tools/perf: Fix the string match for "/tmp/perf-$PID.map" files in dso__load

[PATCH 1/2] tools/perf: Fix the string match for "/tmp/perf-$PID.map" files in dso__load

[Athira Rajeev]

Perf test for perf probe of function from different CU fails
as below:

	./perf test -vv "test perf probe of function from different CU"
	116: test perf probe of function from different CU:
	--- start ---
	test child forked, pid 2679
	Failed to find symbol foo in /tmp/perf-uprobe-different-cu-sh.Msa7iy89bx/testfile
	  Error: Failed to add events.
	--- Cleaning up ---
	"foo" does not hit any event.
	  Error: Failed to delete events.
	---- end(-1) ----
	116: test perf probe of function from different CU                   : FAILED!

The test does below to probe function "foo" :

	# gcc -g -Og -flto -c /tmp/perf-uprobe-different-cu-sh.XniNxNEVT7/testfile-foo.c
	-o /tmp/perf-uprobe-different-cu-sh.XniNxNEVT7/testfile-foo.o
	# gcc -g -Og -c /tmp/perf-uprobe-different-cu-sh.XniNxNEVT7/testfile-main.c
	-o /tmp/perf-uprobe-different-cu-sh.XniNxNEVT7/testfile-main.o
	# gcc -g -Og -o /tmp/perf-uprobe-different-cu-sh.XniNxNEVT7/testfile
	/tmp/perf-uprobe-different-cu-sh.XniNxNEVT7/testfile-foo.o
	/tmp/perf-uprobe-different-cu-sh.XniNxNEVT7/testfile-main.o

	# ./perf probe -x /tmp/perf-uprobe-different-cu-sh.XniNxNEVT7/testfile foo
	Failed to find symbol foo in /tmp/perf-uprobe-different-cu-sh.XniNxNEVT7/testfile
	   Error: Failed to add events.

Perf probe fails to find symbol foo in the executable placed in
/tmp/perf-uprobe-different-cu-sh.XniNxNEVT7

Simple reproduce:

 # mktemp -d /tmp/perf-checkXXXXXXXXXX
   /tmp/perf-checkcWpuLRQI8j

 # gcc -g -o test test.c
 # cp test /tmp/perf-checkcWpuLRQI8j/
 # nm /tmp/perf-checkcWpuLRQI8j/test | grep foo
   00000000100006bc T foo

 # ./perf probe -x /tmp/perf-checkcWpuLRQI8j/test foo
   Failed to find symbol foo in /tmp/perf-checkcWpuLRQI8j/test
      Error: Failed to add events.

But it works with any files like /tmp/perf/test. Only for
patterns with "/tmp/perf-", this fails.

Further debugging, commit 80d496be89ed ("perf report: Add support
for profiling JIT generated code") added support for profiling JIT
generated code. This patch handles dso's of form
"/tmp/perf-$PID.map" .

The check used "if (strncmp(self->name, "/tmp/perf-", 10) == 0)"
to match "/tmp/perf-$PID.map". With this commit, any dso in
/tmp/perf- folder will be considered separately for processing
(not only JIT created map files ). Fix this by changing the
string pattern to check for regex of form "/tmp/perf-*.map"

With the fix,
	# ./perf test "test perf probe of function from different CU"
	117: test perf probe of function from different CU                   : Ok

Signed-off-by: Athira Rajeev<atrajeev@linux.vnet.ibm.com>
---
 tools/perf/util/symbol.c | 12 +++++++++++-
 1 file changed, 11 insertions(+), 1 deletion(-)

diff --git a/tools/perf/util/symbol.c b/tools/perf/util/symbol.c
index 9e5940b5bc59..bfb88a4b0987 100644
--- a/tools/perf/util/symbol.c
+++ b/tools/perf/util/symbol.c
@@ -41,6 +41,7 @@
 #include <limits.h>
 #include <symbol/kallsyms.h>
 #include <sys/utsname.h>
+#include <regex.h>
 
 static int dso__load_kernel_sym(struct dso *dso, struct map *map);
 static int dso__load_guest_kernel_sym(struct dso *dso, struct map *map);
@@ -1797,9 +1798,18 @@ int dso__load(struct dso *dso, struct map *map)
 	struct nscookie nsc;
 	char newmapname[PATH_MAX];
 	const char *map_path = dso__long_name(dso);
+	regex_t    regex;
+	const char *pattern =  "(^/tmp/perf-).*(map)";
 
 	mutex_lock(dso__lock(dso));
-	perfmap = strncmp(dso__name(dso), "/tmp/perf-", 10) == 0;
+	if (regcomp(&regex, pattern, REG_EXTENDED)) {
+		pr_debug("regcomp() failed in dso__load\n");
+		ret = -1;
+		goto out;
+	}
+
+	perfmap = !regexec(&regex, dso__name(dso), 0, NULL, 0);
+
 	if (perfmap) {
 		if (dso__nsinfo(dso) &&
 		    (dso__find_perf_map(newmapname, sizeof(newmapname),
-- 
2.35.3

[PATCH 2/2] tools/perf: Fix parallel-perf python script to replace new python syntax ":=" usage

[Athira Rajeev]

perf test "perf script tests" fails as below in systems
with python 3.6

	File "/home/athira/linux/tools/perf/tests/shell/../../scripts/python/parallel-perf.py", line 442
	if line := p.stdout.readline():
             ^
	SyntaxError: invalid syntax
	--- Cleaning up ---
	---- end(-1) ----
	92: perf script tests: FAILED!

This happens because ":=" is a new syntax that assigns values
to variables as part of a larger expression. This is introduced
from python 3.8 and hence fails in setup with python 3.6
Address this by splitting the large expression and check the
value in two steps:
Previous line: if line := p.stdout.readline():
Current change:
	line = p.stdout.readline()
	if line:

With patch

	./perf test "perf script tests"
	 93: perf script tests:  Ok

Signed-off-by: Athira Rajeev <atrajeev@linux.vnet.ibm.com>
---
 tools/perf/scripts/python/parallel-perf.py | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/tools/perf/scripts/python/parallel-perf.py b/tools/perf/scripts/python/parallel-perf.py
index 21f32ec5ed46..be85fd7f6632 100755
--- a/tools/perf/scripts/python/parallel-perf.py
+++ b/tools/perf/scripts/python/parallel-perf.py
@@ -439,7 +439,8 @@ def ProcessCommandOutputLines(cmd, per_cpu, fn, *x):
 	pat = re.compile(r"\s*\[[0-9]+\]")
 	p = subprocess.Popen(cmd, stdout=subprocess.PIPE)
 	while True:
-		if line := p.stdout.readline():
+		line = p.stdout.readline()
+		if line:
 			line = line.decode("utf-8")
 			if pat.match(line):
 				line = line.split()
-- 
2.35.3

Re: [PATCH 2/2] tools/perf: Fix parallel-perf python script to replace new python syntax ":=" usage

[Adrian Hunter]

On 14/06/24 20:27, Athira Rajeev wrote:
> perf test "perf script tests" fails as below in systems
> with python 3.6
> 
> 	File "/home/athira/linux/tools/perf/tests/shell/../../scripts/python/parallel-perf.py", line 442
> 	if line := p.stdout.readline():
>              ^
> 	SyntaxError: invalid syntax
> 	--- Cleaning up ---
> 	---- end(-1) ----
> 	92: perf script tests: FAILED!
> 
> This happens because ":=" is a new syntax that assigns values
> to variables as part of a larger expression. This is introduced
> from python 3.8 and hence fails in setup with python 3.6

According to below python 3.6 is end-of-life

	https://devguide.python.org/versions/

What was still using python 3.6?

> Address this by splitting the large expression and check the
> value in two steps:
> Previous line: if line := p.stdout.readline():
> Current change:
> 	line = p.stdout.readline()
> 	if line:
> 
> With patch
> 
> 	./perf test "perf script tests"
> 	 93: perf script tests:  Ok
> 
> Signed-off-by: Athira Rajeev <atrajeev@linux.vnet.ibm.com>

Acked-by: Adrian Hunter <adrian.hunter@intel.com>

> ---
>  tools/perf/scripts/python/parallel-perf.py | 3 ++-
>  1 file changed, 2 insertions(+), 1 deletion(-)
> 
> diff --git a/tools/perf/scripts/python/parallel-perf.py b/tools/perf/scripts/python/parallel-perf.py
> index 21f32ec5ed46..be85fd7f6632 100755
> --- a/tools/perf/scripts/python/parallel-perf.py
> +++ b/tools/perf/scripts/python/parallel-perf.py
> @@ -439,7 +439,8 @@ def ProcessCommandOutputLines(cmd, per_cpu, fn, *x):
>  	pat = re.compile(r"\s*\[[0-9]+\]")
>  	p = subprocess.Popen(cmd, stdout=subprocess.PIPE)
>  	while True:
> -		if line := p.stdout.readline():
> +		line = p.stdout.readline()
> +		if line:
>  			line = line.decode("utf-8")
>  			if pat.match(line):
>  				line = line.split()

Re: [PATCH 2/2] tools/perf: Fix parallel-perf python script to replace new python syntax ":=" usage

[Athira Rajeev]

> On 16 Jun 2024, at 8:33 PM, Adrian Hunter <adrian.hunter@intel.com> wrote:
> 
> On 14/06/24 20:27, Athira Rajeev wrote:
>> perf test "perf script tests" fails as below in systems
>> with python 3.6
>> 
>> File "/home/athira/linux/tools/perf/tests/shell/../../scripts/python/parallel-perf.py", line 442
>> if line := p.stdout.readline():
>>             ^
>> SyntaxError: invalid syntax
>> --- Cleaning up ---
>> ---- end(-1) ----
>> 92: perf script tests: FAILED!
>> 
>> This happens because ":=" is a new syntax that assigns values
>> to variables as part of a larger expression. This is introduced
>> from python 3.8 and hence fails in setup with python 3.6
> 
> According to below python 3.6 is end-of-life
> 
> https://devguide.python.org/versions/
> 
> What was still using python 3.6?
> 
>> Address this by splitting the large expression and check the
>> value in two steps:
>> Previous line: if line := p.stdout.readline():
>> Current change:
>> line = p.stdout.readline()
>> if line:
>> 
>> With patch
>> 
>> ./perf test "perf script tests"
>>  93: perf script tests:  Ok
>> 
>> Signed-off-by: Athira Rajeev <atrajeev@linux.vnet.ibm.com>
> 
> Acked-by: Adrian Hunter <adrian.hunter@intel.com>

Observed this on SLES 15 SP5
Thanks for the Acked-by Adrian

I will be posting a V2 adding this Acked-by for this Patch 2 and addressing changes suggested in handling "/tmp/perf-%d.map” files in Patch 1

Thanks
Athira
> 
>> ---
>> tools/perf/scripts/python/parallel-perf.py | 3 ++-
>> 1 file changed, 2 insertions(+), 1 deletion(-)
>> 
>> diff --git a/tools/perf/scripts/python/parallel-perf.py b/tools/perf/scripts/python/parallel-perf.py
>> index 21f32ec5ed46..be85fd7f6632 100755
>> --- a/tools/perf/scripts/python/parallel-perf.py
>> +++ b/tools/perf/scripts/python/parallel-perf.py
>> @@ -439,7 +439,8 @@ def ProcessCommandOutputLines(cmd, per_cpu, fn, *x):
>> pat = re.compile(r"\s*\[[0-9]+\]")
>> p = subprocess.Popen(cmd, stdout=subprocess.PIPE)
>> while True:
>> - if line := p.stdout.readline():
>> + line = p.stdout.readline()
>> + if line:
>> line = line.decode("utf-8")
>> if pat.match(line):
>> line = line.split()

Re: [PATCH 1/2] tools/perf: Fix the string match for "/tmp/perf-$PID.map" files in dso__load

[Adrian Hunter]

On 14/06/24 20:27, Athira Rajeev wrote:
> Perf test for perf probe of function from different CU fails
> as below:
> 
> 	./perf test -vv "test perf probe of function from different CU"
> 	116: test perf probe of function from different CU:
> 	--- start ---
> 	test child forked, pid 2679
> 	Failed to find symbol foo in /tmp/perf-uprobe-different-cu-sh.Msa7iy89bx/testfile
> 	  Error: Failed to add events.
> 	--- Cleaning up ---
> 	"foo" does not hit any event.
> 	  Error: Failed to delete events.
> 	---- end(-1) ----
> 	116: test perf probe of function from different CU                   : FAILED!
> 
> The test does below to probe function "foo" :
> 
> 	# gcc -g -Og -flto -c /tmp/perf-uprobe-different-cu-sh.XniNxNEVT7/testfile-foo.c
> 	-o /tmp/perf-uprobe-different-cu-sh.XniNxNEVT7/testfile-foo.o
> 	# gcc -g -Og -c /tmp/perf-uprobe-different-cu-sh.XniNxNEVT7/testfile-main.c
> 	-o /tmp/perf-uprobe-different-cu-sh.XniNxNEVT7/testfile-main.o
> 	# gcc -g -Og -o /tmp/perf-uprobe-different-cu-sh.XniNxNEVT7/testfile
> 	/tmp/perf-uprobe-different-cu-sh.XniNxNEVT7/testfile-foo.o
> 	/tmp/perf-uprobe-different-cu-sh.XniNxNEVT7/testfile-main.o
> 
> 	# ./perf probe -x /tmp/perf-uprobe-different-cu-sh.XniNxNEVT7/testfile foo
> 	Failed to find symbol foo in /tmp/perf-uprobe-different-cu-sh.XniNxNEVT7/testfile
> 	   Error: Failed to add events.
> 
> Perf probe fails to find symbol foo in the executable placed in
> /tmp/perf-uprobe-different-cu-sh.XniNxNEVT7
> 
> Simple reproduce:
> 
>  # mktemp -d /tmp/perf-checkXXXXXXXXXX
>    /tmp/perf-checkcWpuLRQI8j
> 
>  # gcc -g -o test test.c
>  # cp test /tmp/perf-checkcWpuLRQI8j/
>  # nm /tmp/perf-checkcWpuLRQI8j/test | grep foo
>    00000000100006bc T foo
> 
>  # ./perf probe -x /tmp/perf-checkcWpuLRQI8j/test foo
>    Failed to find symbol foo in /tmp/perf-checkcWpuLRQI8j/test
>       Error: Failed to add events.
> 
> But it works with any files like /tmp/perf/test. Only for
> patterns with "/tmp/perf-", this fails.
> 
> Further debugging, commit 80d496be89ed ("perf report: Add support
> for profiling JIT generated code") added support for profiling JIT
> generated code. This patch handles dso's of form
> "/tmp/perf-$PID.map" .
> 
> The check used "if (strncmp(self->name, "/tmp/perf-", 10) == 0)"
> to match "/tmp/perf-$PID.map". With this commit, any dso in
> /tmp/perf- folder will be considered separately for processing
> (not only JIT created map files ). Fix this by changing the
> string pattern to check for regex of form "/tmp/perf-*.map"
> 
> With the fix,
> 	# ./perf test "test perf probe of function from different CU"
> 	117: test perf probe of function from different CU                   : Ok
> 
> Signed-off-by: Athira Rajeev<atrajeev@linux.vnet.ibm.com>
> ---
>  tools/perf/util/symbol.c | 12 +++++++++++-
>  1 file changed, 11 insertions(+), 1 deletion(-)
> 
> diff --git a/tools/perf/util/symbol.c b/tools/perf/util/symbol.c
> index 9e5940b5bc59..bfb88a4b0987 100644
> --- a/tools/perf/util/symbol.c
> +++ b/tools/perf/util/symbol.c
> @@ -41,6 +41,7 @@
>  #include <limits.h>
>  #include <symbol/kallsyms.h>
>  #include <sys/utsname.h>
> +#include <regex.h>
>  
>  static int dso__load_kernel_sym(struct dso *dso, struct map *map);
>  static int dso__load_guest_kernel_sym(struct dso *dso, struct map *map);
> @@ -1797,9 +1798,18 @@ int dso__load(struct dso *dso, struct map *map)
>  	struct nscookie nsc;
>  	char newmapname[PATH_MAX];
>  	const char *map_path = dso__long_name(dso);
> +	regex_t    regex;
> +	const char *pattern =  "(^/tmp/perf-).*(map)";
>  
>  	mutex_lock(dso__lock(dso));
> -	perfmap = strncmp(dso__name(dso), "/tmp/perf-", 10) == 0;
> +	if (regcomp(&regex, pattern, REG_EXTENDED)) {
> +		pr_debug("regcomp() failed in dso__load\n");
> +		ret = -1;
> +		goto out;
> +	}
> +
> +	perfmap = !regexec(&regex, dso__name(dso), 0, NULL, 0);

This isn't the only place that checks for that name.  Perhaps
create a helper function:

bool is_perf_pid_map_name(const char *name);

Regex looks over complicated.  Maybe sscanf

	int tid;

	return sscanf(name, "/tmp/perf-%d.map", &tid) == 1;

> +
>  	if (perfmap) {
>  		if (dso__nsinfo(dso) &&
>  		    (dso__find_perf_map(newmapname, sizeof(newmapname),