From 1d9a1341c6d9b0f2150a37ec3617eeee01bbfee2 Mon Sep 17 00:00:00 2001

From: "Richard W.M. Jones" <rjones@redhat.com>

Date: Thu, 21 Oct 2021 14:49:52 +0100

Subject: [PATCH] vddk: Refactor how -D vddk.stats=1 is collected

In order to allow us to collect more per-API stats, introduce a global

struct per API for storing these stats.

(cherry picked from commit 3d8657f3d9a2c1b59284333566428b4c7ce32a74)

---

 plugins/vddk/vddk.c | 36 ++++++++++++++++++------------------

 1 file changed, 18 insertions(+), 18 deletions(-)

diff --git a/plugins/vddk/vddk.c b/plugins/vddk/vddk.c

index 80f5870e..3d751544 100644

--- a/plugins/vddk/vddk.c

+++ b/plugins/vddk/vddk.c

@@ -1,5 +1,5 @@

 /* nbdkit

- * Copyright (C) 2013-2020 Red Hat Inc.

+ * Copyright (C) 2013-2021 Red Hat Inc.

  *

  * Redistribution and use in source and binary forms, with or without

  * modification, are permitted provided that the following conditions are

@@ -103,14 +103,23 @@ static bool is_remote;

 /* For each VDDK API define a variable to store the time taken (used

  * to implement -D vddk.stats=1).

  */

+struct vddk_stat {

+  const char *name;             /* function name */

+  int64_t usecs;                /* total number of usecs consumed */

+};

 static pthread_mutex_t stats_lock = PTHREAD_MUTEX_INITIALIZER;

 static void display_stats (void);

-#define STUB(fn,ret,args) static int64_t stats_##fn;

-#define OPTIONAL_STUB(fn,ret,args) static int64_t stats_##fn;

+#define STUB(fn,ret,args) \

+  static struct vddk_stat stats_##fn = { .name = #fn }

+#define OPTIONAL_STUB(fn,ret,args) \

+  static struct vddk_stat stats_##fn = { .name = #fn }

 #include "vddk-stubs.h"

 #undef STUB

 #undef OPTIONAL_STUB

+/* Macros to bracket each VDDK API call, for printing debugging

+ * information and collecting statistics.

+ */

 #define VDDK_CALL_START(fn, fs, ...)                                    \

   do {                                                                  \

   struct timeval start_t, end_t;                                        \

@@ -131,10 +140,11 @@ static void display_stats (void);

   if (vddk_debug_stats) {                               \

     gettimeofday (&end_t, NULL);                        \

     ACQUIRE_LOCK_FOR_CURRENT_SCOPE (&stats_lock);       \

-    stats_##fn += tvdiff_usec (&start_t, &end_t);       \

+    stats_##fn.usecs += tvdiff_usec (&start_t, &end_t); \

   }                                                     \

   } while (0)

+/* Print VDDK errors. */

 #define VDDK_ERROR(err, fs, ...)                                \

   do {                                                          \

     char *vddk_err_msg;                                         \

@@ -167,10 +177,6 @@ vddk_unload (void)

   free (password);

 }

-struct vddk_stat {

-  const char *fn;

-  int64_t usecs;

-};

 DEFINE_VECTOR_TYPE(statlist, struct vddk_stat)

 static int

@@ -179,7 +185,7 @@ stat_compare (const void *vp1, const void *vp2)

   const struct vddk_stat *st1 = vp1;

   const struct vddk_stat *st2 = vp2;

-  /* Note: sorts in reverse order. */

+  /* Note: sorts in reverse order of time spent in each API call. */

   if (st1->usecs < st2->usecs) return 1;

   else if (st1->usecs > st2->usecs) return -1;

   else return 0;

@@ -189,19 +195,13 @@ static void

 display_stats (void)

 {

   statlist stats = empty_vector;

-  struct vddk_stat st;

   size_t i;

-#define ADD_ONE_STAT(fn_, usecs_)               \

-  st.fn = fn_;                                  \

-  st.usecs = usecs_;                            \

-  statlist_append (&stats, st)

-#define STUB(fn,ret,args) ADD_ONE_STAT (#fn, stats_##fn);

-#define OPTIONAL_STUB(fn,ret,args) ADD_ONE_STAT (#fn, stats_##fn);

+#define STUB(fn,ret,args) statlist_append (&stats, stats_##fn)

+#define OPTIONAL_STUB(fn,ret,args) statlist_append (&stats, stats_##fn)

 #include "vddk-stubs.h"

 #undef STUB

 #undef OPTIONAL_STUB

-#undef ADD_ONE_STAT

   qsort (stats.ptr, stats.size, sizeof stats.ptr[0], stat_compare);

@@ -209,7 +209,7 @@ display_stats (void)

   nbdkit_debug ("%-40s  %9s", "", "µs");

   for (i = 0; i < stats.size; ++i) {

     if (stats.ptr[i].usecs)

-      nbdkit_debug ("%-40s %9" PRIi64, stats.ptr[i].fn, stats.ptr[i].usecs);

+      nbdkit_debug ("%-40s %9" PRIi64, stats.ptr[i].name, stats.ptr[i].usecs);

   }

   statlist_reset (&stats);

 }

-- 

2.31.1