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virNetDevOpenvswitchInterfaceStats: Optimize for speed

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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@redhat.com>
Reviewed-by: Ján Tomko <jtomko@redhat.com>
This commit is contained in:
Michal Privoznik 2019-06-28 10:33:09 +02:00
parent f58bcb80b2
commit c297eab525
1 changed files with 74 additions and 37 deletions
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107
src/util/virnetdevopenvswitch.c
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@ -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;
}
#define GET_STAT(name, member) \
do { \
VIR_FREE(output); \
virCommandFree(cmd); \
cmd = virCommandNew(OVSVSCTL); \
virNetDevOpenvswitchAddTimeout(cmd); \
virCommandAddArgList(cmd, "--if-exists", "get", "Interface", \
ifname, "statistics:" name, NULL); \
virCommandSetOutputBuffer(cmd, &output); \
if (virCommandRun(cmd, NULL) < 0 || !output || !*output || *output == '\n') { \
stats->member = -1; \
} else { \
if (virStrToLong_ll(output, &tmp, 10, &stats->member) < 0 || \
*tmp != '\n') { \
virReportError(VIR_ERR_INTERNAL_ERROR, "%s", \
_("Fail to parse ovs-vsctl output")); \
return -1; \
} \
gotStats = true; \
} \
} while (0)
if (!(jsonStats = virJSONValueFromString(output)) ||
!virJSONValueIsArray(jsonStats) ||
!(jsonMap = virJSONValueArrayGet(jsonStats, 1))) {
virReportError(VIR_ERR_INTERNAL_ERROR, "%s",
_("Unable to parse ovs-vsctl output"));
return -1;
}
stats->rx_bytes = stats->rx_packets = stats->rx_errs = stats->rx_drop = -1;
stats->tx_bytes = stats->tx_packets = stats->tx_errs = stats->tx_drop = -1;
for (i = 0; i < virJSONValueArraySize(jsonMap); i++) {
virJSONValuePtr item = virJSONValueArrayGet(jsonMap, i);
virJSONValuePtr jsonKey;
virJSONValuePtr jsonVal;
const char *key;
long long val;
if (!item ||
(!(jsonKey = virJSONValueArrayGet(item, 0))) ||
(!(jsonVal = virJSONValueArrayGet(item, 1))) ||
(!(key = virJSONValueGetString(jsonKey))) ||
(virJSONValueGetNumberLong(jsonVal, &val) < 0)) {
virReportError(VIR_ERR_INTERNAL_ERROR, "%s",
_("Malformed ovs-vsctl output"));
return -1;
}
/* The TX/RX fields appear to be swapped here
* because this is the host view. */
GET_STAT("rx_bytes", tx_bytes);
GET_STAT("rx_packets", tx_packets);
GET_STAT("rx_errors", tx_errs);
GET_STAT("rx_dropped", tx_drop);
GET_STAT("tx_bytes", rx_bytes);
GET_STAT("tx_packets", rx_packets);
GET_STAT("tx_errors", rx_errs);
GET_STAT("tx_dropped", rx_drop);
if (STREQ(key, "rx_bytes")) {
stats->tx_bytes = val;
} else if (STREQ(key, "rx_packets")) {
stats->tx_packets = val;
} else if (STREQ(key, "rx_errors")) {
stats->tx_errs = val;
} else if (STREQ(key, "rx_dropped")) {
stats->tx_drop = val;
} else if (STREQ(key, "tx_bytes")) {
stats->rx_bytes = val;
} else if (STREQ(key, "tx_packets")) {
stats->rx_packets = val;
} else if (STREQ(key, "tx_errors")) {
stats->rx_errs = val;
} else if (STREQ(key, "tx_dropped")) {
stats->rx_drop = val;
} else {
VIR_DEBUG("Unused ovs-vsctl stat key=%s val=%lld", key, val);
}
}
if (!gotStats) {
if (stats->rx_bytes == -1 &&
stats->rx_packets == -1 &&
stats->rx_errs == -1 &&
stats->rx_drop == -1 &&
stats->tx_bytes == -1 &&
stats->tx_packets == -1 &&
stats->tx_errs == -1 &&
stats->tx_drop == -1) {
virReportError(VIR_ERR_INTERNAL_ERROR, "%s",
_("Interface doesn't have any statistics"));
return -1;