qemu: bulk stats: implement block group

This patch implements the VIR_DOMAIN_STATS_BLOCK group of statistics.

To do so, a helper function to get the block stats of all the disks of
a domain is added.

Signed-off-by: Francesco Romani <fromani@redhat.com>
Signed-off-by: Peter Krempa <pkrempa@redhat.com>

include/libvirt/libvirt.h.in

@@ -2517,6 +2517,7 @@ typedef enum {
     VIR_DOMAIN_STATS_BALLOON = (1 << 2), /* return domain balloon info */
     VIR_DOMAIN_STATS_VCPU = (1 << 3), /* return domain virtual CPU info */
     VIR_DOMAIN_STATS_INTERFACE = (1 << 4), /* return domain interfaces info */
+    VIR_DOMAIN_STATS_BLOCK = (1 << 5), /* return domain block info */
 } virDomainStatsTypes;
 
 typedef enum {

src/libvirt.c

@@ -21636,6 +21636,27 @@ virConnectGetDomainCapabilities(virConnectPtr conn,
  * "net.<num>.tx.errs" - transmission errors as unsigned long long.
  * "net.<num>.tx.drop" - transmit packets dropped as unsigned long long.
  *
+ * VIR_DOMAIN_STATS_BLOCK: Return block devices statistics.
+ * The typed parameter keys are in this format:
+ * "block.count" - number of block devices on this domain
+ *                 as unsigned int.
+ * "block.<num>.name" - name of the block device <num> as string.
+ *                      matches the target name (vda/sda/hda) of the
+ *                      block device.
+ * "block.<num>.rd.reqs" - number of read requests as unsigned long long.
+ * "block.<num>.rd.bytes" - number of read bytes as unsigned long long.
+ * "block.<num>.rd.times" - total time (ns) spent on reads as
+ *                          unsigned long long.
+ * "block.<num>.wr.reqs" - number of write requests as unsigned long long.
+ * "block.<num>.wr.bytes" - number of written bytes as unsigned long long.
+ * "block.<num>.wr.times" - total time (ns) spent on writes as
+ *                          unsigned long long.
+ * "block.<num>.fl.reqs" - total flush requests as unsigned long long.
+ * "block.<num>.fl.times" - total time (ns) spent on cache flushing as
+ *                          unsigned long long.
+ * "block.<num>.errors" - Xen only: the 'oo_req' value as
+ *                        unsigned long long.
+ *
  * Using 0 for @stats returns all stats groups supported by the given
  * hypervisor.
  *

src/qemu/qemu_driver.c

@@ -9672,6 +9672,7 @@ qemuDomainBlockStats(virDomainPtr dom,
     return ret;
 }
 
+
 static int
 qemuDomainBlockStatsFlags(virDomainPtr dom,
                           const char *path,
@@ -17651,6 +17652,85 @@ qemuDomainGetStatsInterface(virQEMUDriverPtr driver ATTRIBUTE_UNUSED,
 
 #undef QEMU_ADD_NET_PARAM
 
+/* expects a LL, but typed parameter must be ULL */
+#define QEMU_ADD_BLOCK_PARAM_LL(record, maxparams, num, name, value) \
+do { \
+    char param_name[VIR_TYPED_PARAM_FIELD_LENGTH]; \
+    snprintf(param_name, VIR_TYPED_PARAM_FIELD_LENGTH, \
+             "block.%zu.%s", num, name); \
+    if (value >= 0 && virTypedParamsAddULLong(&(record)->params, \
+                                              &(record)->nparams, \
+                                              maxparams, \
+                                              param_name, \
+                                              value) < 0) \
+        goto cleanup; \
+} while (0)
+
+static int
+qemuDomainGetStatsBlock(virQEMUDriverPtr driver,
+                        virDomainObjPtr dom,
+                        virDomainStatsRecordPtr record,
+                        int *maxparams,
+                        unsigned int privflags)
+{
+    size_t i;
+    int ret = -1;
+    int nstats = dom->def->ndisks;
+    qemuBlockStatsPtr stats = NULL;
+    qemuDomainObjPrivatePtr priv = dom->privateData;
+
+    if (!HAVE_JOB(privflags) || !virDomainObjIsActive(dom))
+        return 0; /* it's ok, just go ahead silently */
+
+    if (VIR_ALLOC_N(stats, nstats) < 0)
+        return -1;
+
+    qemuDomainObjEnterMonitor(driver, dom);
+
+    nstats = qemuMonitorGetAllBlockStatsInfo(priv->mon, NULL,
+                                             stats, nstats);
+
+    qemuDomainObjExitMonitor(driver, dom);
+
+    if (nstats < 0) {
+        virResetLastError();
+        ret = 0; /* still ok, again go ahead silently */
+        goto cleanup;
+    }
+
+    QEMU_ADD_COUNT_PARAM(record, maxparams, "block", dom->def->ndisks);
+
+    for (i = 0; i < nstats; i++) {
+        QEMU_ADD_NAME_PARAM(record, maxparams,
+                            "block", i, dom->def->disks[i]->dst);
+
+        QEMU_ADD_BLOCK_PARAM_LL(record, maxparams, i,
+                                "rd.reqs", stats[i].rd_req);
+        QEMU_ADD_BLOCK_PARAM_LL(record, maxparams, i,
+                                "rd.bytes", stats[i].rd_bytes);
+        QEMU_ADD_BLOCK_PARAM_LL(record, maxparams, i,
+                                "rd.times", stats[i].rd_total_times);
+        QEMU_ADD_BLOCK_PARAM_LL(record, maxparams, i,
+                                "wr.reqs", stats[i].wr_req);
+        QEMU_ADD_BLOCK_PARAM_LL(record, maxparams, i,
+                                "wr.bytes", stats[i].wr_bytes);
+        QEMU_ADD_BLOCK_PARAM_LL(record, maxparams, i,
+                                "wr.times", stats[i].wr_total_times);
+        QEMU_ADD_BLOCK_PARAM_LL(record, maxparams, i,
+                                "fl.reqs", stats[i].flush_req);
+        QEMU_ADD_BLOCK_PARAM_LL(record, maxparams, i,
+                                "fl.times", stats[i].flush_total_times);
+    }
+
+    ret = 0;
+
+ cleanup:
+    VIR_FREE(stats);
+    return ret;
+}
+
+#undef QEMU_ADD_BLOCK_PARAM_LL
+
 #undef QEMU_ADD_NAME_PARAM
 
 #undef QEMU_ADD_COUNT_PARAM
@@ -17674,6 +17754,7 @@ static struct qemuDomainGetStatsWorker qemuDomainGetStatsWorkers[] = {
     { qemuDomainGetStatsBalloon, VIR_DOMAIN_STATS_BALLOON, true },
     { qemuDomainGetStatsVcpu, VIR_DOMAIN_STATS_VCPU, false },
     { qemuDomainGetStatsInterface, VIR_DOMAIN_STATS_INTERFACE, false },
+    { qemuDomainGetStatsBlock, VIR_DOMAIN_STATS_BLOCK, true },
     { NULL, 0, false }
 };
 

src/qemu/qemu_monitor.c

@@ -1756,6 +1756,32 @@ int qemuMonitorGetBlockStatsInfo(qemuMonitorPtr mon,
     return ret;
 }
 
+/* Fills the first 'nstats' block stats. 'stats' must be an array.
+ * Returns <0 on error, otherwise the number of block stats retrieved.
+ * if 'dev_name' is != NULL, look for this device only and skip
+ * any other. In that case return value cannot be greater than 1.
+ */
+int
+qemuMonitorGetAllBlockStatsInfo(qemuMonitorPtr mon,
+                                const char *dev_name,
+                                qemuBlockStatsPtr stats,
+                                int nstats)
+{
+    int ret;
+    VIR_DEBUG("mon=%p dev=%s", mon, dev_name);
+
+    if (mon->json) {
+        ret = qemuMonitorJSONGetAllBlockStatsInfo(mon, dev_name,
+                                                  stats, nstats);
+    } else {
+        virReportError(VIR_ERR_INTERNAL_ERROR, "%s",
+                       _("unable to query all block stats with this QEMU"));
+        return -1;
+    }
+
+    return ret;
+}
+
 /* Return 0 and update @nparams with the number of block stats
  * QEMU supports if success. Return -1 if failure.
  */

src/qemu/qemu_monitor.h

@@ -346,6 +346,26 @@ int qemuMonitorGetBlockStatsInfo(qemuMonitorPtr mon,
                                  long long *flush_req,
                                  long long *flush_total_times,
                                  long long *errs);
+
+typedef struct _qemuBlockStats qemuBlockStats;
+typedef qemuBlockStats *qemuBlockStatsPtr;
+struct _qemuBlockStats {
+    long long rd_req;
+    long long rd_bytes;
+    long long wr_req;
+    long long wr_bytes;
+    long long rd_total_times;
+    long long wr_total_times;
+    long long flush_req;
+    long long flush_total_times;
+};
+
+int qemuMonitorGetAllBlockStatsInfo(qemuMonitorPtr mon,
+                                    const char *dev_name,
+                                    qemuBlockStatsPtr stats,
+                                    int nstats)
+    ATTRIBUTE_NONNULL(1) ATTRIBUTE_NONNULL(3);
+
 int qemuMonitorGetBlockStatsParamsNumber(qemuMonitorPtr mon,
                                          int *nparams);
 

src/qemu/qemu_monitor_json.c

@@ -1734,13 +1734,8 @@ int qemuMonitorJSONGetBlockStatsInfo(qemuMonitorPtr mon,
                                      long long *flush_total_times,
                                      long long *errs)
 {
-    int ret;
-    size_t i;
-    bool found = false;
-    virJSONValuePtr cmd = qemuMonitorJSONMakeCommand("query-blockstats",
-                                                     NULL);
-    virJSONValuePtr reply = NULL;
-    virJSONValuePtr devices;
+    qemuBlockStats stats;
+    int ret = -1;
 
     *rd_req = *rd_bytes = -1;
     *wr_req = *wr_bytes = *errs = -1;
@@ -1754,9 +1749,49 @@ int qemuMonitorJSONGetBlockStatsInfo(qemuMonitorPtr mon,
     if (flush_total_times)
         *flush_total_times = -1;
 
+    if (qemuMonitorJSONGetAllBlockStatsInfo(mon, dev_name, &stats, 1) != 1)
+        goto cleanup;
+
+    *rd_req = stats.rd_req;
+    *rd_bytes = stats.rd_bytes;
+    *wr_req = stats.wr_req;
+    *wr_bytes = stats.wr_bytes;
+    *errs = -1; /* QEMU does not have this */
+
+    if (rd_total_times)
+        *rd_total_times = stats.rd_total_times;
+    if (wr_total_times)
+        *wr_total_times = stats.wr_total_times;
+    if (flush_req)
+        *flush_req = stats.flush_req;
+    if (flush_total_times)
+        *flush_total_times = stats.flush_total_times;
+
+    ret = 0;
+
+ cleanup:
+    return ret;
+}
+
+
+int qemuMonitorJSONGetAllBlockStatsInfo(qemuMonitorPtr mon,
+                                        const char *dev_name,
+                                        qemuBlockStatsPtr bstats,
+                                        int nstats)
+{
+    int ret, count;
+    size_t i;
+    virJSONValuePtr cmd = qemuMonitorJSONMakeCommand("query-blockstats",
+                                                     NULL);
+    virJSONValuePtr reply = NULL;
+    virJSONValuePtr devices;
+
     if (!cmd)
         return -1;
 
+    if (!bstats || nstats <= 0)
+        return -1;
+
     ret = qemuMonitorJSONCommand(mon, cmd, &reply);
 
     if (ret == 0)
@@ -1772,108 +1807,123 @@ int qemuMonitorJSONGetBlockStatsInfo(qemuMonitorPtr mon,
         goto cleanup;
     }
 
-    for (i = 0; i < virJSONValueArraySize(devices); i++) {
+    count = 0;
+    for (i = 0; i < virJSONValueArraySize(devices) && count < nstats; i++) {
         virJSONValuePtr dev = virJSONValueArrayGet(devices, i);
         virJSONValuePtr stats;
-        const char *thisdev;
         if (!dev || dev->type != VIR_JSON_TYPE_OBJECT) {
             virReportError(VIR_ERR_INTERNAL_ERROR, "%s",
-                           _("blockstats device entry was not in expected format"));
+                           _("blockstats device entry was not "
+                             "in expected format"));
             goto cleanup;
         }
 
-        if ((thisdev = virJSONValueObjectGetString(dev, "device")) == NULL) {
-            virReportError(VIR_ERR_INTERNAL_ERROR, "%s",
-                           _("blockstats device entry was not in expected format"));
-            goto cleanup;
-        }
-
-        /* New QEMU has separate names for host & guest side of the disk
-         * and libvirt gives the host side a 'drive-' prefix. The passed
-         * in dev_name is the guest side though
+        /* If dev_name is specified, we are looking for a specific device,
+         * so we must be stricter.
          */
-        if (STRPREFIX(thisdev, QEMU_DRIVE_HOST_PREFIX))
-            thisdev += strlen(QEMU_DRIVE_HOST_PREFIX);
+        if (dev_name) {
+            const char *thisdev = virJSONValueObjectGetString(dev, "device");
+            if (!thisdev) {
+                virReportError(VIR_ERR_INTERNAL_ERROR, "%s",
+                               _("blockstats device entry was not "
+                                 "in expected format"));
+                goto cleanup;
+            }
 
-        if (STRNEQ(thisdev, dev_name))
-            continue;
+            /* New QEMU has separate names for host & guest side of the disk
+             * and libvirt gives the host side a 'drive-' prefix. The passed
+             * in dev_name is the guest side though
+             */
+            if (STRPREFIX(thisdev, QEMU_DRIVE_HOST_PREFIX))
+                thisdev += strlen(QEMU_DRIVE_HOST_PREFIX);
+
+            if (STRNEQ(thisdev, dev_name))
+                continue;
+        }
 
-        found = true;
         if ((stats = virJSONValueObjectGet(dev, "stats")) == NULL ||
             stats->type != VIR_JSON_TYPE_OBJECT) {
             virReportError(VIR_ERR_INTERNAL_ERROR, "%s",
-                           _("blockstats stats entry was not in expected format"));
+                           _("blockstats stats entry was not "
+                             "in expected format"));
             goto cleanup;
         }
 
-        if (virJSONValueObjectGetNumberLong(stats, "rd_bytes", rd_bytes) < 0) {
+        if (virJSONValueObjectGetNumberLong(stats, "rd_bytes",
+                                            &bstats->rd_bytes) < 0) {
             virReportError(VIR_ERR_INTERNAL_ERROR,
                            _("cannot read %s statistic"),
                            "rd_bytes");
             goto cleanup;
         }
-        if (virJSONValueObjectGetNumberLong(stats, "rd_operations", rd_req) < 0) {
+        if (virJSONValueObjectGetNumberLong(stats, "rd_operations",
+                                            &bstats->rd_req) < 0) {
             virReportError(VIR_ERR_INTERNAL_ERROR,
                            _("cannot read %s statistic"),
                             "rd_operations");
             goto cleanup;
         }
-        if (rd_total_times &&
-            virJSONValueObjectHasKey(stats, "rd_total_time_ns") &&
+        if (virJSONValueObjectHasKey(stats, "rd_total_time_ns") &&
             (virJSONValueObjectGetNumberLong(stats, "rd_total_time_ns",
-                                             rd_total_times) < 0)) {
+                                             &bstats->rd_total_times) < 0)) {
             virReportError(VIR_ERR_INTERNAL_ERROR,
                            _("cannot read %s statistic"),
                            "rd_total_time_ns");
             goto cleanup;
         }
-        if (virJSONValueObjectGetNumberLong(stats, "wr_bytes", wr_bytes) < 0) {
+        if (virJSONValueObjectGetNumberLong(stats, "wr_bytes",
+                                            &bstats->wr_bytes) < 0) {
             virReportError(VIR_ERR_INTERNAL_ERROR,
                            _("cannot read %s statistic"),
                            "wr_bytes");
             goto cleanup;
         }
-        if (virJSONValueObjectGetNumberLong(stats, "wr_operations", wr_req) < 0) {
+        if (virJSONValueObjectGetNumberLong(stats, "wr_operations",
+                                            &bstats->wr_req) < 0) {
             virReportError(VIR_ERR_INTERNAL_ERROR,
                            _("cannot read %s statistic"),
                            "wr_operations");
             goto cleanup;
         }
-        if (wr_total_times &&
-            virJSONValueObjectHasKey(stats, "wr_total_time_ns") &&
+        if (virJSONValueObjectHasKey(stats, "wr_total_time_ns") &&
             (virJSONValueObjectGetNumberLong(stats, "wr_total_time_ns",
-                                             wr_total_times) < 0)) {
+                                             &bstats->wr_total_times) < 0)) {
             virReportError(VIR_ERR_INTERNAL_ERROR,
                            _("cannot read %s statistic"),
                            "wr_total_time_ns");
             goto cleanup;
         }
-        if (flush_req &&
-            virJSONValueObjectHasKey(stats, "flush_operations") &&
+        if (virJSONValueObjectHasKey(stats, "flush_operations") &&
             (virJSONValueObjectGetNumberLong(stats, "flush_operations",
-                                            flush_req) < 0)) {
+                                             &bstats->flush_req) < 0)) {
             virReportError(VIR_ERR_INTERNAL_ERROR,
                            _("cannot read %s statistic"),
                            "flush_operations");
             goto cleanup;
         }
-        if (flush_total_times &&
-            virJSONValueObjectHasKey(stats, "flush_total_time_ns") &&
+        if (virJSONValueObjectHasKey(stats, "flush_total_time_ns") &&
             (virJSONValueObjectGetNumberLong(stats, "flush_total_time_ns",
-                                            flush_total_times) < 0)) {
+                                             &bstats->flush_total_times) < 0)) {
             virReportError(VIR_ERR_INTERNAL_ERROR,
                            _("cannot read %s statistic"),
                            "flush_total_time_ns");
             goto cleanup;
         }
+
+        count++;
+        bstats++;
+
+        if (dev_name && count)
+            break;
     }
 
-    if (!found) {
+    if (dev_name && !count) {
         virReportError(VIR_ERR_INTERNAL_ERROR,
                        _("cannot find statistics for device '%s'"), dev_name);
         goto cleanup;
     }
-    ret = 0;
+
+    ret = count;
 
  cleanup:
     virJSONValueFree(cmd);

src/qemu/qemu_monitor_json.h

@@ -79,6 +79,10 @@ int qemuMonitorJSONGetBlockStatsInfo(qemuMonitorPtr mon,
                                      long long *flush_req,
                                      long long *flush_total_times,
                                      long long *errs);
+int qemuMonitorJSONGetAllBlockStatsInfo(qemuMonitorPtr mon,
+                                        const char *dev_name,
+                                        qemuBlockStatsPtr stats,
+                                        int nstats);
 int qemuMonitorJSONGetBlockStatsParamsNumber(qemuMonitorPtr mon,
                                              int *nparams);
 int qemuMonitorJSONGetBlockExtent(qemuMonitorPtr mon,