@@ -1160,6 +1160,8 @@ struct fgraph_ops {
void *private;
trace_func_graph_ent_t saved_func;
int idx;
+ /* If skip_timestamp is true, this does not record timestamps. */
+ bool skip_timestamp;
};
void *fgraph_reserve_data(int idx, int size_bytes);
@@ -174,6 +174,7 @@ int ftrace_graph_active;
static struct fgraph_ops *fgraph_array[FGRAPH_ARRAY_SIZE];
static unsigned long fgraph_array_bitmask;
+static bool fgraph_skip_timestamp;
/* LRU index table for fgraph_array */
static int fgraph_lru_table[FGRAPH_ARRAY_SIZE];
@@ -557,7 +558,11 @@ ftrace_push_return_trace(unsigned long ret, unsigned long func,
return -EBUSY;
}
- calltime = trace_clock_local();
+ /* This is not really 'likely' but for keeping the least path to be faster. */
+ if (likely(fgraph_skip_timestamp))
+ calltime = 0LL;
+ else
+ calltime = trace_clock_local();
offset = READ_ONCE(current->curr_ret_stack);
ret_stack = RET_STACK(current, offset);
@@ -728,6 +733,12 @@ ftrace_pop_return_trace(struct ftrace_graph_ret *trace, unsigned long *ret,
*ret = ret_stack->ret;
trace->func = ret_stack->func;
trace->calltime = ret_stack->calltime;
+ /* This is not really 'likely' but for keeping the least path to be faster. */
+ if (likely(!trace->calltime))
+ trace->rettime = 0LL;
+ else
+ trace->rettime = trace_clock_local();
+
trace->overrun = atomic_read(¤t->trace_overrun);
trace->depth = current->curr_ret_depth;
/*
@@ -788,7 +799,6 @@ __ftrace_return_to_handler(struct ftrace_regs *fregs, unsigned long frame_pointe
return (unsigned long)panic;
}
- trace.rettime = trace_clock_local();
if (fregs)
ftrace_regs_set_instruction_pointer(fregs, ret);
@@ -1248,6 +1258,24 @@ static void ftrace_graph_disable_direct(bool disable_branch)
fgraph_direct_gops = &fgraph_stub;
}
+static void update_fgraph_skip_timestamp(void)
+{
+ int i;
+
+ for (i = 0; i < FGRAPH_ARRAY_SIZE; i++) {
+ struct fgraph_ops *gops = fgraph_array[i];
+
+ if (gops == &fgraph_stub)
+ continue;
+
+ if (!gops->skip_timestamp) {
+ fgraph_skip_timestamp = false;
+ return;
+ }
+ }
+ fgraph_skip_timestamp = true;
+}
+
int register_ftrace_graph(struct fgraph_ops *gops)
{
int command = 0;
@@ -1271,6 +1299,7 @@ int register_ftrace_graph(struct fgraph_ops *gops)
gops->idx = i;
ftrace_graph_active++;
+ update_fgraph_skip_timestamp();
if (ftrace_graph_active == 2)
ftrace_graph_disable_direct(true);
@@ -1303,6 +1332,7 @@ int register_ftrace_graph(struct fgraph_ops *gops)
ftrace_graph_active--;
gops->saved_func = NULL;
fgraph_lru_release_index(i);
+ update_fgraph_skip_timestamp();
}
out:
mutex_unlock(&ftrace_lock);
@@ -1326,8 +1356,8 @@ void unregister_ftrace_graph(struct fgraph_ops *gops)
goto out;
fgraph_array[gops->idx] = &fgraph_stub;
-
ftrace_graph_active--;
+ update_fgraph_skip_timestamp();
if (!ftrace_graph_active)
command = FTRACE_STOP_FUNC_RET;
@@ -345,6 +345,7 @@ NOKPROBE_SYMBOL(fprobe_return);
static struct fgraph_ops fprobe_graph_ops = {
.entryfunc = fprobe_entry,
.retfunc = fprobe_return,
+ .skip_timestamp = true,
};
static int fprobe_graph_active;