Pavel Chromy: performance tweak of gdb_put_packet_inner() removing malloc and avoidin...

git-svn-id: svn://svn.berlios.de/openocd/trunk@453 b42882b7-edfa-0310-969c-e2dbd0fdcd60

diff --git a/src/server/gdb_server.c b/src/server/gdb_server.c
index c7200d20cea377802dab5bd48e78bf13b17a9921..1fac46972a9e4f6c9c3bae36313f396012272421 100644 (file)
--- a/src/server/gdb_server.c
+++ b/src/server/gdb_server.c
@@ -314,33 +314,29 @@ int gdb_put_packet_inner(connection_t *connection, char *buffer, int len)
                free(debug_buffer);
 #endif
 
-               void *allocated = NULL;
-               char stackAlloc[1024];
-               char *t = stackAlloc;
-               int totalLen = 1 + len + 1 + 2;
-               if (totalLen > sizeof(stackAlloc))
+               char local_buffer[1024];
+               local_buffer[0] = '$';
+               if (len+4 <= sizeof(local_buffer))
                {
-                       allocated = malloc(totalLen);
-                       t = allocated;
-                       if (allocated == NULL)
-                       {
-                               ERROR("Ran out of memory trying to reply packet %d\n", totalLen);
-                               exit(-1);
-                       }
+                       /* performance gain on smaller packets by only a single call to gdb_write() */
+                       memcpy(local_buffer+1, buffer, len++);
+                       local_buffer[len++] = '#';
+                       local_buffer[len++] = DIGITS[(my_checksum >> 4) & 0xf];
+                       local_buffer[len++] = DIGITS[my_checksum & 0xf];
+                       gdb_write(connection, local_buffer, len);
                }
-               t[0] = '$';
-               memcpy(t + 1, buffer, len);
-               t[1 + len] = '#';
-               t[1 + len + 1] = DIGITS[(my_checksum >> 4) & 0xf];
-               t[1 + len + 2] = DIGITS[my_checksum & 0xf];
-
-               gdb_write(connection, t, totalLen);
-
-               if (allocated)
+               else
                {
-                       free(allocated);
+                       /* larger packets are transmitted directly from caller supplied buffer
+                          by several calls to gdb_write() to avoid dynamic allocation */
+                       local_buffer[1] = '#';
+                       local_buffer[2] = DIGITS[(my_checksum >> 4) & 0xf];
+                       local_buffer[3] = DIGITS[my_checksum & 0xf];
+                       gdb_write(connection, local_buffer, 1);
+                       gdb_write(connection, buffer, len);
+                       gdb_write(connection, local_buffer+1, 3);
                }
-               
+
                if ((retval = gdb_get_char(connection, &reply)) != ERROR_OK)
                        return retval;
 
@@ -688,7 +684,7 @@ int gdb_new_connection(connection_t *connection)
         * GDB connection will fail if e.g. register read packets fail,
         * otherwise resetting/halting the target could have been left to GDB init
         * scripts
-     */
+        */
        if (((retval = gdb_service->target->type->halt(gdb_service->target)) != ERROR_OK) &&
                        (retval != ERROR_TARGET_ALREADY_HALTED))
        {
@@ -1387,18 +1383,18 @@ void xml_printf(int *retval, char **xml, int *pos, int *size, const char *fmt, .
                        }
                }
 
-           va_list ap;
-           int ret;
-           va_start(ap, fmt);
-           ret = vsnprintf(*xml + *pos, *size - *pos, fmt, ap);
-           va_end(ap);
-           if ((ret > 0) && ((ret + 1) < *size - *pos))
-           {
-               *pos += ret;
-               return;
-           }
-           /* there was just enough or not enough space, allocate more. */
-           first = 0;
+               va_list ap;
+               int ret;
+               va_start(ap, fmt);
+               ret = vsnprintf(*xml + *pos, *size - *pos, fmt, ap);
+               va_end(ap);
+               if ((ret > 0) && ((ret + 1) < *size - *pos))
+               {
+                       *pos += ret;
+                       return;
+               }
+               /* there was just enough or not enough space, allocate more. */
+               first = 0;
        }
 }