Revision 9c29bcd189f4ab1644b7125713602532d0aefdb7 authored by Eric Dumazet on 21 September 2018, 22:27:48 UTC, committed by David S. Miller on 24 September 2018, 04:55:25 UTC
As diagnosed by Song Liu, ndo_poll_controller() can be very dangerous on loaded hosts, since the cpu calling ndo_poll_controller() might steal all NAPI contexts (for all RX/TX queues of the NIC). This capture can last for unlimited amount of time, since one cpu is generally not able to drain all the queues under load. mlx5 uses NAPI for TX completions, so we better let core networking stack call the napi->poll() to avoid the capture. Signed-off-by: Eric Dumazet <edumazet@google.com> Cc: Saeed Mahameed <saeedm@mellanox.com> Signed-off-by: David S. Miller <davem@davemloft.net>
1 parent a24b66c
perf-with-kcore.sh
#!/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
![swh spinner](/static/img/swh-spinner.gif)
Computing file changes ...