1 files changed, 57 insertions, 0 deletions
diff --git a/tapset/http_request.stp b/tapset/http_request.stp
index 5df785c..ceac883 100644
--- a/tapset/http_request.stp
+++ b/tapset/http_request.stp
@@ -2,6 +2,7 @@
  global cmogstored_http_req_begin;
  global cmogstored_http_pipelined;
  global cmogstored_http_addr;
+global cmogstored_fd_by_tid;
  
  probe process("cmogstored").mark("http_accepted") {
          fd = $arg1;
@@ -13,12 +14,62 @@ probe process("cmogstored").mark("http_accepted") {
          cmogstored_http_addr[pid(),fd] = host_serv;
  }
  
+/*
+ * mog_ioq_ready..ioq_reschedule   = time waiting for others to finish IO
+ * ioq_reschedule..mog_ioq_unblock = time inside epoll ready list
+ */
+
+/* associate the fd with thread for the function return */
+probe process("cmogstored").function("mog_ioq_ready") {
+        cmogstored_fd_by_tid[tid()] = @cast($mfd, "struct mog_fd")->fd;
+}
+
+/*
+ * if mog_ioq_ready returns false, we are blocked waiting on I/O and
+ * will hit ioq_reschedule
+ */
+probe process("cmogstored").function("mog_ioq_ready").return {
+        if (!$return)
+                printf("% 6d % 6d ioq blocked\n",
+                        pid(), cmogstored_fd_by_tid[tid()]);
+}
+
+/*
+ * we hit ioq_reschedule when we are ready to enter the epoll ready-list
+ * we will hit mog_ioq_unblock eventually
+ */
+probe process("cmogstored").mark("ioq_reschedule") {
+        fd = @cast($mfd, "struct mog_fd")->fd;
+        printf("% 6d % 6d ioq reschedule_enter\n", pid(), fd);
+}
+
+/* associate the fd with thread for the function return */
+probe process("cmogstored").function("mog_ioq_unblock") {
+        cmogstored_fd_by_tid[tid()] = @cast($mfd, "struct mog_fd")->fd;
+}
+
+/*
+ * if mog_ioq_unblock returns true, it means the fd was previously
+ * in ioq_reschedule
+ */
+probe process("cmogstored").function("mog_ioq_unblock").return {
+        if ($return)
+                printf("% 6d % 6d ioq reschedule_done\n",
+                        pid(), cmogstored_fd_by_tid[tid()]);
+}
+
+/*
+ * HTTP client disconnected
+ */
  probe process("cmogstored").function("http_close") {
          fd = @cast($mfd, "struct mog_fd")->fd;
          printf("% 6d % 6d closing\n", pid(), fd);
          delete cmogstored_http_addr[pid(),fd];
  }
  
+/*
+ * We start reading/buffering the HTTP request here
+ */
  probe process("cmogstored").mark("http_req_begin") {
          fd = @cast($mfd, "struct mog_fd")->fd;
          is_pipelined = $arg1;
@@ -26,6 +77,9 @@ probe process("cmogstored").mark("http_req_begin") {
          cmogstored_http_pipelined[pid(),fd] = is_pipelined;
  }
  
+/*
+ * we start processing the HTTP request (opening/stat-ing files)
+ */
  probe process("cmogstored").function("http_process_client") {
          fd = @cast($mfd, "struct mog_fd")->fd;
          starttime = cmogstored_http_req_begin[pid(),fd];
@@ -36,6 +90,9 @@ probe process("cmogstored").function("http_process_client") {
                  pid(), fd, diff, is_pipelined ? "true" : "false");
  }
  
+/*
+ * We blocked on writing (HTTP headers) to the client socket
+ */
  probe process("cmogstored").mark("write_buffered") {
          printf("% 6d % 6d blocked with %lu bytes to write\n",
                  pid(), $fd, $len);