Re: [PATCH] parallels: add block device statistics to driver

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On 05/22/2015 10:42 AM, Nikolay Shirokovskiy wrote:
Statistics provided through PCS SDK. As we have only async interface in SDK we
need to be subscribed to statistics in order to get it. Trivial solution on
every stat request to subscribe, wait event and then unsubscribe will lead to
significant delays in case of a number of successive requests, as the event
will be delivered on next PCS server notify cycle. On the other hand we don't
want to keep unnesessary subscribtion. So we take an hibrid solution to
subcsribe on first request and then keep a subscription while requests are
active. We populate cache of statistics on subscribtion events and use this
cache to serve libvirts requests.

Signed-off-by: Nikolay Shirokovskiy <nshirokovskiy@xxxxxxxxxxxxx>
---
  src/parallels/parallels_driver.c |  106 +++++++++++++++++++++
  src/parallels/parallels_sdk.c    |  193 ++++++++++++++++++++++++++++++++------
  src/parallels/parallels_sdk.h    |    2 +
  src/parallels/parallels_utils.h  |   15 +++
  4 files changed, 285 insertions(+), 31 deletions(-)

diff --git a/src/parallels/parallels_driver.c b/src/parallels/parallels_driver.c
index 4b87213..ce59e00 100644
--- a/src/parallels/parallels_driver.c
+++ b/src/parallels/parallels_driver.c
@@ -51,6 +51,7 @@
  #include "nodeinfo.h"
  #include "virstring.h"
  #include "cpu/cpu.h"
+#include "virtypedparam.h"
#include "parallels_driver.h"
  #include "parallels_utils.h"
@@ -1179,6 +1180,109 @@ parallelsDomainGetMaxMemory(virDomainPtr domain)
      return ret;
  }
+static int
+parallelsDomainBlockStats(virDomainPtr domain, const char *path,
+                     virDomainBlockStatsPtr stats)
+{
+    virDomainObjPtr dom = NULL;
+    int ret = -1;
+    size_t i;
+    int idx;
+
+    if (!(dom = parallelsDomObjFromDomain(domain)))
+        return -1;
+
+    if (*path) {
+        if ((idx = virDomainDiskIndexByName(dom->def, path, false)) < 0) {
+            virReportError(VIR_ERR_INVALID_ARG, _("invalid path: %s"), path);
+            goto cleanup;
+        }
+        if (prlsdkGetBlockStats(dom, dom->def->disks[idx], stats) < 0)
+            goto cleanup;
+    } else {
+        virDomainBlockStatsStruct s;
+
+#define PARALLELS_ZERO_STATS(VAR, TYPE, NAME)           \
+        stats->VAR = 0;
+
+        PARALLELS_BLOCK_STATS_FOREACH(PARALLELS_ZERO_STATS)
+
+#undef PARALLELS_ZERO_STATS
+

Why don't you use memset here?

+        for (i = 0; i < dom->def->ndisks; i++) {
+            if (prlsdkGetBlockStats(dom, dom->def->disks[i], &s) < 0)
+                goto cleanup;
+
+#define     PARALLELS_SUM_STATS(VAR, TYPE, NAME)        \
+            if (s.VAR != -1)                            \
+                stats->VAR += s.VAR;
+
+            PARALLELS_BLOCK_STATS_FOREACH(PARALLELS_SUM_STATS)
+
+#undef      PARALLELS_SUM_STATS
+        }
+    }
+    stats->errs = -1;
+    ret = 0;
+
+ cleanup:
+    if (dom)
+        virObjectUnlock(dom);
+
+    return ret;
+}
+
+static int
+parallelsDomainBlockStatsFlags(virDomainPtr domain,
+                          const char *path,
+                          virTypedParameterPtr params,
+                          int *nparams,
+                          unsigned int flags)
+{
+    virDomainBlockStatsStruct stats;
+    int ret = -1;
+    size_t i;
+
+    virCheckFlags(VIR_TYPED_PARAM_STRING_OKAY, -1);
+    /* We don't return strings, and thus trivially support this flag.  */
+    flags &= ~VIR_TYPED_PARAM_STRING_OKAY;
+
+    if (parallelsDomainBlockStats(domain, path, &stats) < 0)
+        goto cleanup;
+
+    if (*nparams == 0) {
+#define PARALLELS_COUNT_STATS(VAR, TYPE, NAME)       \
+        if ((stats.VAR) != -1)                       \
+            ++*nparams;
+
+        PARALLELS_BLOCK_STATS_FOREACH(PARALLELS_COUNT_STATS)
+
+#undef PARALLELS_COUNT_STATS
+        ret = 0;
+        goto cleanup;
+    }
+
+    i = 0;
+#define PARALLELS_BLOCK_STATS_ASSIGN_PARAM(VAR, TYPE, NAME)                    \
+    if (i < *nparams && (stats.VAR) != -1) {                                   \
+        if (virTypedParameterAssign(params + i, TYPE,                          \
+                                    VIR_TYPED_PARAM_LLONG, (stats.VAR)) < 0)   \
+            goto cleanup;                                                      \
+        i++;                                                                   \
+    }
+
+    PARALLELS_BLOCK_STATS_FOREACH(PARALLELS_BLOCK_STATS_ASSIGN_PARAM)
+
+#undef PARALLELS_BLOCK_STATS_ASSIGN_PARAM
+
+    *nparams = i;
+    ret = 0;
+
+ cleanup:
+    return ret;
+}
+
+
  static virHypervisorDriver parallelsDriver = {
      .name = "Parallels",
      .connectOpen = parallelsConnectOpen,            /* 0.10.0 */
@@ -1228,6 +1332,8 @@ static virHypervisorDriver parallelsDriver = {
      .domainManagedSave = parallelsDomainManagedSave, /* 1.2.14 */
      .domainManagedSaveRemove = parallelsDomainManagedSaveRemove, /* 1.2.14 */
      .domainGetMaxMemory = parallelsDomainGetMaxMemory, /* 1.2.15 */
+    .domainBlockStats = parallelsDomainBlockStats, /* 1.2.16 */
+    .domainBlockStatsFlags = parallelsDomainBlockStatsFlags, /* 1.2.16 */

Could you, please, update there versions to 1.2.17?
  };
static virConnectDriver parallelsConnectDriver = {
diff --git a/src/parallels/parallels_sdk.c b/src/parallels/parallels_sdk.c
index 88ad59b..eb8d965 100644
--- a/src/parallels/parallels_sdk.c
+++ b/src/parallels/parallels_sdk.c
@@ -21,6 +21,7 @@
   */

....
+        goto cleanup;
+
      switch (prlEventType) {
          case PET_DSP_EVT_VM_STATE_CHANGED:
+            prlsdkHandleVmStateEvent(privconn, prlEvent, uuid);
+            break;
          case PET_DSP_EVT_VM_CONFIG_CHANGED:
+            prlsdkHandleVmConfigEvent(privconn, uuid);
+            break;
          case PET_DSP_EVT_VM_CREATED:
          case PET_DSP_EVT_VM_ADDED:
+            prlsdkHandleVmAddedEvent(privconn, uuid);
+            break;
          case PET_DSP_EVT_VM_DELETED:
          case PET_DSP_EVT_VM_UNREGISTERED:
-            pret = prlsdkHandleVmEvent(privconn, prlEvent);
+            prlsdkHandleVmRemovedEvent(privconn, uuid);
+            break;
+        case PET_DSP_EVT_VM_PERFSTATS:
+            prlsdkHandlePerfEvent(privconn, prlEvent, uuid);
+            // above function takes own of event
+            prlEvent = PRL_INVALID_HANDLE;
              break;
          default:
              VIR_DEBUG("Skipping event of type %d", prlEventType);
@@ -3455,3 +3481,108 @@ prlsdkDomainManagedSaveRemove(virDomainObjPtr dom)
return 0;
  }
+

Could you describe the idea with stats cache in more detail? Why do you keer up to 3 prlsdk stats, but use only one? And where do you free these handles?

+static int
+prlsdkExtractStatsParam(PRL_HANDLE sdkstats, const char *name, long long *val)
+{
+    PRL_HANDLE param = PRL_INVALID_HANDLE;
+    PRL_RESULT pret;
+    PRL_INT64 pval = 0;
+    int ret = -1;
+
+    pret = PrlEvent_GetParamByName(sdkstats, name, &param);
+    if (pret == PRL_ERR_NO_DATA) {
+        *val = -1;
+        ret = 0;
+        goto cleanup;
+    } else if (PRL_FAILED(pret)) {
+        logPrlError(pret);
+        goto cleanup;
+    }
+    pret = PrlEvtPrm_ToInt64(param, &pval);
+    prlsdkCheckRetGoto(pret, cleanup);
+
+    *val = pval;
+    ret = 0;
+
+ cleanup:
+    PrlHandle_Free(param);
+    return ret;
+}
+
+static int
+prlsdkGetStatsParam(virDomainObjPtr dom, const char *name, long long *val)
+{
+    parallelsDomObjPtr privdom = dom->privateData;
+    PRL_HANDLE job = PRL_INVALID_HANDLE;
+
+    if (privdom->cache.stats != PRL_INVALID_HANDLE) {
+        privdom->cache.count = 0;
+        return prlsdkExtractStatsParam(privdom->cache.stats, name, val);
+    }
+
+    job = PrlVm_SubscribeToPerfStats(privdom->sdkdom, NULL);
+    if (PRL_FAILED(waitJob(job)))
+        goto error;
+
+    while (privdom->cache.stats == PRL_INVALID_HANDLE) {
+        if (virCondWait(&privdom->cache.cond, &dom->parent.lock) < 0) {
+            virReportError(VIR_ERR_INTERNAL_ERROR, "%s",
+                           _("Unable to wait on monitor condition"));
+            goto error;
+        }
+    }
+
+    return prlsdkExtractStatsParam(privdom->cache.stats, name, val);
+ error:
+    return -1;
+}
+
+int
+prlsdkGetBlockStats(virDomainObjPtr dom, virDomainDiskDefPtr disk, virDomainBlockStatsPtr stats)
+{
+    virDomainDeviceDriveAddressPtr address;
+    int idx;
+    const char *prefix;
+    int ret = -1;
+    char *name = NULL;
+
+    address = &disk->info.addr.drive;
+    switch (disk->bus) {
+    case VIR_DOMAIN_DISK_BUS_IDE:
+        prefix = "ide";
+        idx = address->bus * 2 + address->unit;
+        break;
+    case VIR_DOMAIN_DISK_BUS_SATA:
+        prefix = "sata";
+        idx = address->unit;
+        break;
+    case VIR_DOMAIN_DISK_BUS_SCSI:
+        prefix = "scsi";
+        idx = address->unit;
+        break;
+    default:
+        virReportError(VIR_ERR_INTERNAL_ERROR,
+                   _("Unknown disk bus: %X"), disk->bus);
+        goto cleanup;
+    }
+

I think this won't work if the domain has disks on different buses.


+
+#define PRLSDK_GET_STAT_PARAM(VAL, TYPE, NAME)                          \
+    if (virAsprintf(&name, "devices.%s%d.%s", prefix, idx, NAME) < 0)   \
+        goto cleanup;                                                   \
+    if (prlsdkGetStatsParam(dom, name, &stats->VAL) < 0)                \
+        goto cleanup;                                                   \
+    VIR_FREE(name);
+
+    PARALLELS_BLOCK_STATS_FOREACH(PRLSDK_GET_STAT_PARAM)
+
+#undef PRLSDK_GET_STAT_PARAM
+
+    ret = 0;
+
+ cleanup:
+
+    VIR_FREE(name);
+    return ret;
+}
diff --git a/src/parallels/parallels_sdk.h b/src/parallels/parallels_sdk.h
index 3f17fc8..afa6745 100644
--- a/src/parallels/parallels_sdk.h
+++ b/src/parallels/parallels_sdk.h
@@ -64,3 +64,5 @@ int
  prlsdkAttachVolume(virDomainObjPtr dom, virDomainDiskDefPtr disk);
  int
  prlsdkDetachVolume(virDomainObjPtr dom, virDomainDiskDefPtr disk);
+int
+prlsdkGetBlockStats(virDomainObjPtr dom, virDomainDiskDefPtr disk, virDomainBlockStatsPtr stats);
diff --git a/src/parallels/parallels_utils.h b/src/parallels/parallels_utils.h
index 2d1d405..e424405 100644
--- a/src/parallels/parallels_utils.h
+++ b/src/parallels/parallels_utils.h
@@ -73,11 +73,20 @@ struct _parallelsConn {
  typedef struct _parallelsConn parallelsConn;
  typedef struct _parallelsConn *parallelsConnPtr;
+struct _parallelsContersCache {
+    PRL_HANDLE stats;
+    virCond cond;
+    int count;
+};
+
+typedef struct _parallelsContersCache parallelsContersCache;
+
  struct parallelsDomObj {
      int id;
      char *uuid;
      char *home;
      PRL_HANDLE sdkdom;
+    parallelsContersCache cache;
  };
typedef struct parallelsDomObj *parallelsDomObjPtr;
@@ -106,4 +115,10 @@ virStorageVolPtr parallelsStorageVolLookupByPathLocked(virConnectPtr conn,
  int parallelsStorageVolDefRemove(virStoragePoolObjPtr privpool,
                                   virStorageVolDefPtr privvol);
+#define PARALLELS_BLOCK_STATS_FOREACH(OP) \
+            OP(rd_req, VIR_DOMAIN_BLOCK_STATS_READ_REQ, "read_requests")    \
+            OP(rd_bytes, VIR_DOMAIN_BLOCK_STATS_READ_BYTES, "read_total")   \
+            OP(wr_req, VIR_DOMAIN_BLOCK_STATS_WRITE_REQ, "write_requests")  \
+            OP(wr_bytes, VIR_DOMAIN_BLOCK_STATS_WRITE_BYTES, "write_total")
+
  #endif

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