Commit c501e90b authored by Adrian Hunter's avatar Adrian Hunter Committed by Arnaldo Carvalho de Melo
Browse files

perf tools: Add perf-with-kcore script 



Decoding an Intel PT trace of the kernel requires an accurate kernel
object image.  This is provided by making a copy of kcore.  However the
copy needs to be made under the same conditions as the original
recording, and then it needs to be associated with the perf.data file.
The perf-with-kcore script does that.

The script also checks the permissions on the buildid cache and can be
used to fix them.  That is needed for distributions where root does not
have a home directory and consequently writes to the same buildid cache
as the user, resulting in cached files that the user does not have
access to.

Example:

$ ./perf-with-kcore
Usage: perf-with-kcore <perf sub-command> <perf.data directory> [<sub-command options> [ -- <workload>]]
       <perf sub-command> can be record, script, report or inject
   or: perf-with-kcore fix_buildid_cache_permissions
$ ./perf-with-kcore record pt_uname -e intel_pt// -- uname
Recording
Using /home/ahunter/bin/perf
perf version 3.15.rc3.g4549ba
/home/ahunter/bin/perf record -o pt_uname/perf.data -e intel_pt//  -- uname
Linux
[ perf record: Woken up 3 times to write data ]
[ perf record: Captured and wrote 0.023 MB pt_uname/perf.data ]
Copying kcore
[sudo] password for ahunter:
Done
$ tools/perf/perf-with-kcore.sh script pt_uname | head
Using /home/ahunter/bin/perf
perf version 3.15.rc3.g4549ba
/home/ahunter/bin/perf script -i pt_uname/perf.data --kallsyms=pt_uname/kcore_dir/kallsyms
         swapper     0 [002] 161533.969666: sched:sched_switch: swapper/2:0 [120] R ==> perf:11316 [120]
          :11315 11315 [003] 161533.969704: sched:sched_switch: perf:11315 [120] S ==> swapper/3:0 [120]
          :11316 11316 [002] 161533.969783: sched:sched_switch: perf:11316 [120] R ==> migration/2:33 [0]
             :33    33 [002] 161533.969791: sched:sched_switch: migration/2:33 [0] S ==> swapper/2:0 [120]
         swapper     0 [003] 161533.969792: sched:sched_switch: swapper/3:0 [120] R ==> perf:11316 [120]
          :11316 11316 [003] 161533.970062: branches:                 0 [unknown] ([unknown]) => ffffffff810532fa native_write_msr_safe ([kernel.kallsyms])
          :11316 11316 [003] 161533.970062: branches:  ffffffff810532fd native_write_msr_safe ([kernel.kallsyms]) => ffffffff81035b31 pt_config_start ([kernel.kallsyms])

Signed-off-by: default avatarAdrian Hunter <adrian.hunter@intel.com>
Cc: David Ahern <dsahern@gmail.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Namhyung Kim <namhyung@gmail.com>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephane Eranian <eranian@google.com>
Link: http://lkml.kernel.org/r/1406786474-9306-30-git-send-email-adrian.hunter@intel.com


Signed-off-by: default avatarArnaldo Carvalho de Melo <acme@redhat.com>
parent ad962273

tools/perf/.gitignore

+1 −0
Original line number Diff line number Diff line
@@ -15,6 +15,7 @@ perf.data 
perf.data.old

output.svg

perf-archive

perf-with-kcore

tags

TAGS

cscope*

tools/perf/Makefile.perf

+4 −1
Original line number Diff line number Diff line
@@ -126,6 +126,7 @@ PYRF_OBJS = 
SCRIPT_SH =



SCRIPT_SH += perf-archive.sh

SCRIPT_SH += perf-with-kcore.sh



grep-libs = $(filter -l%,$(1))

strip-libs = $(filter-out -l%,$(1))
@@ -878,6 +879,8 @@ install-bin: all install-gtk 
		$(INSTALL) -d -m 755 '$(DESTDIR_SQ)$(perfexec_instdir_SQ)'

	$(call QUIET_INSTALL, perf-archive) \

		$(INSTALL) $(OUTPUT)perf-archive -t '$(DESTDIR_SQ)$(perfexec_instdir_SQ)'

	$(call QUIET_INSTALL, perf-with-kcore) \

		$(INSTALL) $(OUTPUT)perf-with-kcore -t '$(DESTDIR_SQ)$(perfexec_instdir_SQ)'

ifndef NO_LIBPERL

	$(call QUIET_INSTALL, perl-scripts) \

		$(INSTALL) -d -m 755 '$(DESTDIR_SQ)$(perfexec_instdir_SQ)/scripts/perl/Perf-Trace-Util/lib/Perf/Trace'; \
@@ -923,7 +926,7 @@ config-clean: 
	@$(MAKE) -C config/feature-checks clean >/dev/null



clean: $(LIBTRACEEVENT)-clean $(LIBAPIKFS)-clean config-clean

	$(call QUIET_CLEAN, core-objs)  $(RM) $(LIB_OBJS) $(BUILTIN_OBJS) $(LIB_FILE) $(OUTPUT)perf-archive $(OUTPUT)perf.o $(LANG_BINDINGS) $(GTK_OBJS)

	$(call QUIET_CLEAN, core-objs)  $(RM) $(LIB_OBJS) $(BUILTIN_OBJS) $(LIB_FILE) $(OUTPUT)perf-archive $(OUTPUT)perf-with-kcore $(OUTPUT)perf.o $(LANG_BINDINGS) $(GTK_OBJS)

	$(call QUIET_CLEAN, core-progs) $(RM) $(ALL_PROGRAMS) perf

	$(call QUIET_CLEAN, core-gen)   $(RM)  *.spec *.pyc *.pyo */*.pyc */*.pyo $(OUTPUT)common-cmds.h TAGS tags cscope* $(OUTPUT)PERF-VERSION-FILE $(OUTPUT)PERF-CFLAGS $(OUTPUT)PERF-FEATURES $(OUTPUT)util/*-bison* $(OUTPUT)util/*-flex*

	$(QUIET_SUBDIR0)Documentation $(QUIET_SUBDIR1) clean

tools/perf/perf-with-kcore.sh

0 → 100644
+259 −0
Original line number Diff line number Diff line 
#!/bin/bash

# perf-with-kcore: use perf with a copy of kcore

# Copyright (c) 2014, Intel Corporation.

#

# This program is free software; you can redistribute it and/or modify it

# under the terms and conditions of the GNU General Public License,

# version 2, as published by the Free Software Foundation.

#

# This program is distributed in the hope it will be useful, but WITHOUT

# ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or

# FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for

# more details.



set -e



usage()

{

        echo "Usage: perf-with-kcore <perf sub-command> <perf.data directory> [<sub-command options> [ -- <workload>]]" >&2

        echo "       <perf sub-command> can be record, script, report or inject" >&2

        echo "   or: perf-with-kcore fix_buildid_cache_permissions" >&2

        exit 1

}



find_perf()

{

	if [ -n "$PERF" ] ; then

		return

	fi

	PERF=`which perf || true`

	if [ -z "$PERF" ] ; then

		echo "Failed to find perf" >&2

	        exit 1

	fi

	if [ ! -x "$PERF" ] ; then

		echo "Failed to find perf" >&2

	        exit 1

	fi

	echo "Using $PERF"

	"$PERF" version

}



copy_kcore()

{

	echo "Copying kcore"



	if [ $EUID -eq 0 ] ; then

		SUDO=""

	else

		SUDO="sudo"

	fi



	rm -f perf.data.junk

	("$PERF" record -o perf.data.junk $PERF_OPTIONS -- sleep 60) >/dev/null 2>/dev/null &

	PERF_PID=$!



	# Need to make sure that perf has started

	sleep 1



	KCORE=$(($SUDO "$PERF" buildid-cache -v -f -k /proc/kcore >/dev/null) 2>&1)

	case "$KCORE" in

	"kcore added to build-id cache directory "*)

		KCORE_DIR=${KCORE#"kcore added to build-id cache directory "}

	;;

	*)

		kill $PERF_PID

		wait >/dev/null 2>/dev/null || true

		rm perf.data.junk

		echo "$KCORE"

		echo "Failed to find kcore" >&2

		exit 1

	;;

	esac



	kill $PERF_PID

	wait >/dev/null 2>/dev/null || true

	rm perf.data.junk



	$SUDO cp -a "$KCORE_DIR" "$(pwd)/$PERF_DATA_DIR"

	$SUDO rm -f "$KCORE_DIR/kcore"

	$SUDO rm -f "$KCORE_DIR/kallsyms"

	$SUDO rm -f "$KCORE_DIR/modules"

	$SUDO rmdir "$KCORE_DIR"



	KCORE_DIR_BASENAME=$(basename "$KCORE_DIR")

	KCORE_DIR="$(pwd)/$PERF_DATA_DIR/$KCORE_DIR_BASENAME"



	$SUDO chown $UID "$KCORE_DIR"

	$SUDO chown $UID "$KCORE_DIR/kcore"

	$SUDO chown $UID "$KCORE_DIR/kallsyms"

	$SUDO chown $UID "$KCORE_DIR/modules"



	$SUDO chgrp $GROUPS "$KCORE_DIR"

	$SUDO chgrp $GROUPS "$KCORE_DIR/kcore"

	$SUDO chgrp $GROUPS "$KCORE_DIR/kallsyms"

	$SUDO chgrp $GROUPS "$KCORE_DIR/modules"



	ln -s "$KCORE_DIR_BASENAME" "$PERF_DATA_DIR/kcore_dir"

}



fix_buildid_cache_permissions()

{

	if [ $EUID -ne 0 ] ; then

		echo "This script must be run as root via sudo " >&2

		exit 1

	fi



	if [ -z "$SUDO_USER" ] ; then

		echo "This script must be run via sudo" >&2

		exit 1

	fi



	USER_HOME=$(bash <<< "echo ~$SUDO_USER")



	if [ "$HOME" != "$USER_HOME" ] ; then

		echo "Fix unnecessary because root has a home: $HOME" >&2

		exit 1

	fi



	echo "Fixing buildid cache permissions"



	find "$USER_HOME/.debug" -xdev -type d          ! -user "$SUDO_USER" -ls -exec chown    "$SUDO_USER" \{\} \;

	find "$USER_HOME/.debug" -xdev -type f -links 1 ! -user "$SUDO_USER" -ls -exec chown    "$SUDO_USER" \{\} \;

	find "$USER_HOME/.debug" -xdev -type l          ! -user "$SUDO_USER" -ls -exec chown -h "$SUDO_USER" \{\} \;



	if [ -n "$SUDO_GID" ] ; then

		find "$USER_HOME/.debug" -xdev -type d          ! -group "$SUDO_GID" -ls -exec chgrp    "$SUDO_GID" \{\} \;

		find "$USER_HOME/.debug" -xdev -type f -links 1 ! -group "$SUDO_GID" -ls -exec chgrp    "$SUDO_GID" \{\} \;

		find "$USER_HOME/.debug" -xdev -type l          ! -group "$SUDO_GID" -ls -exec chgrp -h "$SUDO_GID" \{\} \;

	fi



	echo "Done"

}



check_buildid_cache_permissions()

{

	if [ $EUID -eq 0 ] ; then

		return

	fi



	PERMISSIONS_OK+=$(find "$HOME/.debug" -xdev -type d          ! -user "$USER" -print -quit)

	PERMISSIONS_OK+=$(find "$HOME/.debug" -xdev -type f -links 1 ! -user "$USER" -print -quit)

	PERMISSIONS_OK+=$(find "$HOME/.debug" -xdev -type l          ! -user "$USER" -print -quit)



	PERMISSIONS_OK+=$(find "$HOME/.debug" -xdev -type d          ! -group "$GROUPS" -print -quit)

	PERMISSIONS_OK+=$(find "$HOME/.debug" -xdev -type f -links 1 ! -group "$GROUPS" -print -quit)

	PERMISSIONS_OK+=$(find "$HOME/.debug" -xdev -type l          ! -group "$GROUPS" -print -quit)



	if [ -n "$PERMISSIONS_OK" ] ; then

		echo "*** WARNING *** buildid cache permissions may need fixing" >&2

	fi

}



record()

{

	echo "Recording"



	if [ $EUID -ne 0 ] ; then



		if [ "$(cat /proc/sys/kernel/kptr_restrict)" -ne 0 ] ; then

			echo "*** WARNING *** /proc/sys/kernel/kptr_restrict prevents access to kernel addresses" >&2

		fi



		if echo "$PERF_OPTIONS" | grep -q ' -a \|^-a \| -a$\|^-a$\| --all-cpus \|^--all-cpus \| --all-cpus$\|^--all-cpus$' ; then

			echo "*** WARNING *** system-wide tracing without root access will not be able to read all necessary information from /proc" >&2

		fi



		if echo "$PERF_OPTIONS" | grep -q 'intel_pt\|intel_bts\| -I\|^-I' ; then

			if [ "$(cat /proc/sys/kernel/perf_event_paranoid)" -gt -1 ] ; then

				echo "*** WARNING *** /proc/sys/kernel/perf_event_paranoid restricts buffer size and tracepoint (sched_switch) use" >&2

			fi



			if echo "$PERF_OPTIONS" | grep -q ' --per-thread \|^--per-thread \| --per-thread$\|^--per-thread$' ; then

				true

			elif echo "$PERF_OPTIONS" | grep -q ' -t \|^-t \| -t$\|^-t$' ; then

				true

			elif [ ! -r /sys/kernel/debug -o ! -x /sys/kernel/debug ] ; then

				echo "*** WARNING *** /sys/kernel/debug permissions prevent tracepoint (sched_switch) use" >&2

			fi

		fi

	fi



	if [ -z "$1" ] ; then

		echo "Workload is required for recording" >&2

		usage

	fi



	if [ -e "$PERF_DATA_DIR" ] ; then

		echo "'$PERF_DATA_DIR' exists" >&2

		exit 1

	fi



	find_perf



	mkdir "$PERF_DATA_DIR"



	echo "$PERF record -o $PERF_DATA_DIR/perf.data $PERF_OPTIONS -- $*"

	"$PERF" record -o "$PERF_DATA_DIR/perf.data" $PERF_OPTIONS -- $* || true



	if rmdir "$PERF_DATA_DIR" > /dev/null 2>/dev/null ; then

		exit 1

	fi



	copy_kcore



	echo "Done"

}



subcommand()

{

	find_perf

	check_buildid_cache_permissions

	echo "$PERF $PERF_SUB_COMMAND -i $PERF_DATA_DIR/perf.data --kallsyms=$PERF_DATA_DIR/kcore_dir/kallsyms $*"

	"$PERF" $PERF_SUB_COMMAND -i "$PERF_DATA_DIR/perf.data" "--kallsyms=$PERF_DATA_DIR/kcore_dir/kallsyms" $*

}



if [ "$1" = "fix_buildid_cache_permissions" ] ; then

	fix_buildid_cache_permissions

	exit 0

fi



PERF_SUB_COMMAND=$1

PERF_DATA_DIR=$2

shift || true

shift || true



if [ -z "$PERF_SUB_COMMAND" ] ; then

	usage

fi



if [ -z "$PERF_DATA_DIR" ] ; then

	usage

fi



case "$PERF_SUB_COMMAND" in

"record")

	while [ "$1" != "--" ] ; do

		PERF_OPTIONS+="$1 "

		shift || break

	done

	if [ "$1" != "--" ] ; then

		echo "Options and workload are required for recording" >&2

		usage

	fi

	shift

	record $*

;;

"script")

	subcommand $*

;;

"report")

	subcommand $*

;;

"inject")

	subcommand $*

;;

*)

	usage

;;

esac

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