mir/ovs
2
0
Fork 0
mirror of https://github.com/openvswitch/ovs synced 2025-09-02 15:25:22 +00:00
Code Issues Releases Wiki Activity

xenserver: Renice netback process to priority 0 by default.

Browse Source 
Under heavy VM network load, we have observed that ovs-vswitchd can be
starved for CPU time, which prevents flows from being set up.  This can
in turn cause connections to XAPI in Dom0 to time out (among other issues).

It is probably not necessary to renice netback all the way to priority 0
as done in this commit.  That is simply the value that we have tested.  QA
has not reported any ill side-effects of this choice of value (yet).  One
reasonable alternative, should any problems be noticed, would be to leave
netback at its default -5 priority and simply boost ovs-vswitchd's priority
to say -6 or -7.

Bug #1656.
This commit is contained in:
Ben Pfaff
2009-08-19 15:59:18 -07:00
parent 612f6d49c5
commit 641a0a4ed0
2 changed files with 35 additions and 0 deletions
Download Patch File Download Diff File Expand all files Collapse all files

28
xenserver/etc_init.d_vswitch
View File

@@ -34,6 +34,7 @@ VSWITCHD_CONF="${VSWITCHD_CONF:-/etc/ovs-vswitchd.conf}"
VSWITCHD_PIDFILE="${VSWITCHD_PIDFILE:-/var/run/ovs-vswitchd.pid}"
VSWITCHD_RUN_DIR="${VSWITCHD_RUN_DIR:-/var/xen/vswitch}"
VSWITCHD_PRIORITY="${VSWITCHD_PRIORITY:--5}"
VSWITCHD_NETBACK_PRIORITY="${VSWITCHD_NETBACK_PRIORITY:-0}"
VSWITCHD_LOGFILE="${VSWITCHD_LOGFILE:-/var/log/ovs-vswitchd.log}"
VSWITCHD_FILE_LOGLEVEL="${VSWITCHD_FILE_LOGLEVEL:-}"
VSWITCHD_SYSLOG_LOGLEVEL="${VSWITCHD_SYSLOG_LOGLEVEL:-WARN}"
@@ -115,6 +116,28 @@ function reload_vswitchd {
fi
}
function quietly {
"$@" > /dev/null
}
# renice_netback PRIORITY PID [PID...]
#
# Renices the netback processes given as each PID to nice level PRIORITY.
function renice_netback {
local pri=$1
shift
if test $# = 0; then
warning "Netback not running, nothing to renice"
return
fi
for pid
do
action "Renicing netback (pid $pid) to priority $pri" quietly renice $pri -p $pid
done
}
function start_vswitchd {
local syslog_opt="-vANY:SYSLOG:${VSWITCHD_SYSLOG_LOGLEVEL}"
local logfile_file_opt=""
@@ -152,6 +175,11 @@ function start_vswitchd {
if [ "$ENABLE_FAKE_PROC_NET" = "y" ]; then
fake_proc_net_opt="--fake-proc-net"
fi
if [ "$VSWITCHD_NETBACK_PRIORITY" != default ]; then
renice_netback $VSWITCHD_NETBACK_PRIORITY $(pidof netback)
else
warning "Netback renicing disabled (see /etc/sysconfig/vswitch)"
fi
if [ "$daemonize" != "y" ]; then
# Start in background and force a "success" message
action "Starting ovs-vswitchd ($strace_opt$valgrind_opt)" true

7
xenserver/etc_sysconfig_vswitch.example
View File

@@ -43,6 +43,13 @@
# processes.
# VSWITCHD_PRIORITY=-5
# VSWITCHD_NETBACK_PRIORITY: "nice" priority at which to run netback.
# It is a good idea to run ovs-vswitchd at a higher priority than
# netback to ensure that it gets enough CPU time to set up flows
# (bug #1656). Set this to 'default' to avoid changing netback's
# priority.
# VSWITCHD_NETBACK_PRIORITY=0
# VSWITCHD_LOGFILE: File to send the FILE_LOGLEVEL log messages to.
# VSWITCHD_LOGFILE=/var/log/ovs-vswitchd.log