Re: [libvirt] [PATCH 1/3] virNetDevOpenvswitchInterfaceStats: Optimize for speed

We run 'ovs-vsctl' nine times (first to find if interface is there and then eight times = for each stats member separately). This is very inefficient. I've found a way to run it once and with a bit of help from virJSON module we can parse out stats we need. Signed-off-by: Michal Privoznik <mprivozn(a)redhat.com&gt; --- src/util/virnetdevopenvswitch.c | 111 +++++++++++++++++++++----------- 1 file changed, 74 insertions(+), 37 deletions(-) diff --git a/src/util/virnetdevopenvswitch.c b/src/util/virnetdevopenvswitch.c index c99ecfbf15..0fe64bedab 100644 --- a/src/util/virnetdevopenvswitch.c +++ b/src/util/virnetdevopenvswitch.c @@ -28,6 +28,7 @@ #include "virmacaddr.h" #include "virstring.h" #include "virlog.h" +#include "virjson.h" #define VIR_FROM_THIS VIR_FROM_NONE @@ -311,58 +312,94 @@ int virNetDevOpenvswitchInterfaceStats(const char *ifname, virDomainInterfaceStatsPtr stats) { - char *tmp; - bool gotStats = false; VIR_AUTOPTR(virCommand) cmd = NULL; VIR_AUTOFREE(char *) output = NULL; + VIR_AUTOPTR(virJSONValue) jsonStats = NULL; + virJSONValuePtr jsonMap = NULL; + size_t i; - /* Just ensure the interface exists in ovs */ cmd = virCommandNew(OVSVSCTL); virNetDevOpenvswitchAddTimeout(cmd); - virCommandAddArgList(cmd, "get", "Interface", ifname, "name", NULL); + virCommandAddArgList(cmd, "--if-exists", "--format=list", "--data=json", + "--no-headings", "--columns=statistics", "list", + "Interface", ifname, NULL);

virCommandSetOutputBuffer(cmd, &output); - if (virCommandRun(cmd, NULL) < 0) { + /* The above command returns either: + * 1) empty string if @ifname doesn't exist, or + * 2) a JSON array, for instance: + * ["map",[["collisions",0],["rx_bytes",0],["rx_crc_err",0],["rx_dropped",0], + * ["rx_errors",0],["rx_frame_err",0],["rx_over_err",0],["rx_packets",0], + * ["tx_bytes",12406],["tx_dropped",0],["tx_errors",0],["tx_packets",173]]] + */ +

+ if (virCommandRun(cmd, NULL) < 0 || + STREQ_NULLABLE(output, "")) { /* no ovs-vsctl or interface 'ifname' doesn't exists in ovs */ virReportError(VIR_ERR_INTERNAL_ERROR, "%s", _("Interface not found")); return -1; }