stack: change gettimeofday() to clock_gettime()

For achieving the above, needed below changes too.

* more sanity into how 'frame->op' is assigned.
* infra to have 'stats' as separate section in 'xlator_t' structure

Updates #137

Change-Id: I36679bf9577f3ed00a695b4e7d92870dcb3db8e1
Signed-off-by: Amar Tumballi <amarts@redhat.com>

1 files changed, 33 insertions, 19 deletions

diff --git a/libglusterfs/src/stack.h b/libglusterfs/src/stack.h
index 856a9a4786e..8a617377bc7 100644
--- a/libglusterfs/src/stack.h
+++ b/libglusterfs/src/stack.h
@@ -32,6 +32,7 @@ typedef struct call_pool call_pool_t;
 #include "lkowner.h"
 #include "client_t.h"
 #include "libglusterfs-messages.h"
+#include "timespec.h"
 
 #define NFS_PID 1
 #define LOW_PRIO_PROC_PID -1
@@ -72,9 +73,9 @@ struct _call_frame {
         void         *cookie;      /* unique cookie */
         gf_boolean_t  complete;
 
-        glusterfs_fop_t op;
-        struct timeval begin;      /* when this frame was created */
-        struct timeval end;        /* when this frame completed */
+        glusterfs_fop_t  op;
+        struct timespec  begin;      /* when this frame was created */
+        struct timespec  end;        /* when this frame completed */
         const char      *wind_from;
         const char      *wind_to;
         const char      *unwind_from;
@@ -112,7 +113,7 @@ struct _call_stack {
 
         int32_t                       op;
         int8_t                        type;
-        struct timeval                tv;
+        struct timespec               tv;
         xlator_t                     *err_xl;
         int32_t                       error;
 };
@@ -129,18 +130,17 @@ struct _call_stack {
 
 
 struct xlator_fops;
+void gf_update_latency (call_frame_t *frame);
 
-void
-gf_latency_begin (call_frame_t *frame, void *fn);
-
-void
-gf_latency_end (call_frame_t *frame);
 
 static inline void
 FRAME_DESTROY (call_frame_t *frame)
 {
         void *local = NULL;
 
+        if (frame->root->ctx->measure_latency)
+                gf_update_latency (frame);
+
         list_del_init (&frame->frames);
         if (frame->local) {
                 local = frame->local;
@@ -225,6 +225,18 @@ STACK_RESET (call_stack_t *stack)
         } while (0);                                                   \
 
 
+/* NOTE: make sure to keep this as an macro, mainly because, we need 'fn'
+   field here to be the proper fn ptr, so its address is valid entry in
+   'xlator_fops' struct.
+   To understand this, check the `xlator.h:struct xlator_fops`, and then
+   see a STACK_WIND call, which generally calls `subvol->fops->fop`, so
+   the address offset should give the index */
+
+/* +1 is required as 0 means NULL fop, and we don't have a variable for it */
+#define get_fop_index_from_fn(xl, fn)                                   \
+        (1 + (((long)&(fn) - (long)&((xl)->fops->stat)) / sizeof (void *)))
+
+
 /* make a call without switching frames */
 #define STACK_WIND_TAIL(frame, obj, fn, params ...)                     \
         do {                                                            \
@@ -295,7 +307,8 @@ STACK_RESET (call_stack_t *stack)
                               frame->root, old_THIS->name,              \
                               THIS->name);                              \
                 if (obj->ctx->measure_latency)                          \
-                        gf_latency_begin (_new, fn);                    \
+                        timespec_now (&_new->begin);                    \
+                _new->op = get_fop_index_from_fn ((_new->this), (fn));  \
                 fn (_new, obj, params);                                 \
                 THIS = old_THIS;                                        \
         } while (0)
@@ -304,9 +317,9 @@ STACK_RESET (call_stack_t *stack)
 #define STACK_UNWIND STACK_UNWIND_STRICT
 
 /* return from function in type-safe way */
-#define STACK_UNWIND_STRICT(op, frame, op_ret, op_errno, params ...)    \
+#define STACK_UNWIND_STRICT(fop, frame, op_ret, op_errno, params ...)   \
         do {                                                            \
-                fop_##op##_cbk_t      fn = NULL;                        \
+                fop_##fop##_cbk_t      fn = NULL;                       \
                 call_frame_t *_parent = NULL;                           \
                 xlator_t     *old_THIS = NULL;                          \
                                                                         \
@@ -329,7 +342,7 @@ STACK_RESET (call_stack_t *stack)
                                       frame->root, THIS->name,          \
                                       (int32_t)(op_ret));               \
                 }                                                       \
-                fn = (fop_##op##_cbk_t )frame->ret;                     \
+                fn = (fop_##fop##_cbk_t)frame->ret;                     \
                 _parent = frame->parent;                                \
                 LOCK(&frame->root->stack_lock);                         \
                 {                                                       \
@@ -348,8 +361,12 @@ STACK_RESET (call_stack_t *stack)
                 THIS = _parent->this;                                   \
                 frame->complete = _gf_true;                             \
                 frame->unwind_from = __FUNCTION__;                      \
-                if (frame->this->ctx->measure_latency)                  \
-                        gf_latency_end (frame);                         \
+                if (frame->this->ctx->measure_latency) {                \
+                        timespec_now (&frame->end);                     \
+                        /* required for top most xlator */              \
+                        if (_parent->ret == NULL)                       \
+                                timespec_now (&_parent->end);           \
+                }                                                       \
                 fn (_parent, frame->cookie, _parent->this, op_ret,      \
                     op_errno, params);                                  \
                 THIS = old_THIS;                                        \
@@ -454,10 +471,7 @@ copy_frame (call_frame_t *frame)
         newstack->ctx = oldstack->ctx;
 
         if (newstack->ctx->measure_latency) {
-                if (gettimeofday (&newstack->tv, NULL) == -1)
-                        gf_msg ("stack", GF_LOG_ERROR, errno,
-                                LG_MSG_GETTIMEOFDAY_FAILED,
-                                "gettimeofday () failed.");
+                timespec_now (&newstack->tv);
                 memcpy (&newframe->begin, &newstack->tv,
                         sizeof (newstack->tv));
         }