1 files changed, 50 insertions, 48 deletions

diff --git a/scripts/pybootchartgui/pybootchartgui/draw.py b/scripts/pybootchartgui/pybootchartgui/draw.py
index bddd8048c9..ec5dd333a1 100644
--- a/scripts/pybootchartgui/pybootchartgui/draw.py
+++ b/scripts/pybootchartgui/pybootchartgui/draw.py
@@ -344,56 +344,58 @@ def render_charts(ctx, options, clip, trace, curr_y, w, h, sec_w):
         proc_tree = options.proc_tree(trace)
 
         # render bar legend
-        ctx.set_font_size(LEGEND_FONT_SIZE)
-
-        draw_legend_box(ctx, "CPU (user+sys)", CPU_COLOR, off_x, curr_y+20, leg_s)
-        draw_legend_box(ctx, "I/O (wait)", IO_COLOR, off_x + 120, curr_y+20, leg_s)
-
-        # render I/O wait
-        chart_rect = (off_x, curr_y+30, w, bar_h)
-        if clip_visible (clip, chart_rect):
-                draw_box_ticks (ctx, chart_rect, sec_w)
-                draw_annotations (ctx, proc_tree, trace.times, chart_rect)
-                draw_chart (ctx, IO_COLOR, True, chart_rect, \
-                            [(sample.time, sample.user + sample.sys + sample.io) for sample in trace.cpu_stats], \
-                            proc_tree, None)
-                # render CPU load
-                draw_chart (ctx, CPU_COLOR, True, chart_rect, \
-                            [(sample.time, sample.user + sample.sys) for sample in trace.cpu_stats], \
-                            proc_tree, None)
-
-        curr_y = curr_y + 30 + bar_h
+        if trace.cpu_stats:
+                ctx.set_font_size(LEGEND_FONT_SIZE)
+
+                draw_legend_box(ctx, "CPU (user+sys)", CPU_COLOR, off_x, curr_y+20, leg_s)
+                draw_legend_box(ctx, "I/O (wait)", IO_COLOR, off_x + 120, curr_y+20, leg_s)
+
+                # render I/O wait
+                chart_rect = (off_x, curr_y+30, w, bar_h)
+                if clip_visible (clip, chart_rect):
+                        draw_box_ticks (ctx, chart_rect, sec_w)
+                        draw_annotations (ctx, proc_tree, trace.times, chart_rect)
+                        draw_chart (ctx, IO_COLOR, True, chart_rect, \
+                                    [(sample.time, sample.user + sample.sys + sample.io) for sample in trace.cpu_stats], \
+                                    proc_tree, None)
+                        # render CPU load
+                        draw_chart (ctx, CPU_COLOR, True, chart_rect, \
+                                    [(sample.time, sample.user + sample.sys) for sample in trace.cpu_stats], \
+                                    proc_tree, None)
+
+                curr_y = curr_y + 30 + bar_h
 
         # render second chart
-        draw_legend_line(ctx, "Disk throughput", DISK_TPUT_COLOR, off_x, curr_y+20, leg_s)
-        draw_legend_box(ctx, "Disk utilization", IO_COLOR, off_x + 120, curr_y+20, leg_s)
-
-        # render I/O utilization
-        chart_rect = (off_x, curr_y+30, w, bar_h)
-        if clip_visible (clip, chart_rect):
-                draw_box_ticks (ctx, chart_rect, sec_w)
-                draw_annotations (ctx, proc_tree, trace.times, chart_rect)
-                draw_chart (ctx, IO_COLOR, True, chart_rect, \
-                            [(sample.time, sample.util) for sample in trace.disk_stats], \
-                            proc_tree, None)
-
-        # render disk throughput
-        max_sample = max (trace.disk_stats, key = lambda s: s.tput)
-        if clip_visible (clip, chart_rect):
-                draw_chart (ctx, DISK_TPUT_COLOR, False, chart_rect, \
-                            [(sample.time, sample.tput) for sample in trace.disk_stats], \
-                            proc_tree, None)
-
-        pos_x = off_x + ((max_sample.time - proc_tree.start_time) * w / proc_tree.duration)
-
-        shift_x, shift_y = -20, 20
-        if (pos_x < off_x + 245):
-                shift_x, shift_y = 5, 40
-
-        label = "%dMB/s" % round ((max_sample.tput) / 1024.0)
-        draw_text (ctx, label, DISK_TPUT_COLOR, pos_x + shift_x, curr_y + shift_y)
-
-        curr_y = curr_y + 30 + bar_h
+        if trace.disk_stats:
+                draw_legend_line(ctx, "Disk throughput", DISK_TPUT_COLOR, off_x, curr_y+20, leg_s)
+                draw_legend_box(ctx, "Disk utilization", IO_COLOR, off_x + 120, curr_y+20, leg_s)
+
+                # render I/O utilization
+                chart_rect = (off_x, curr_y+30, w, bar_h)
+                if clip_visible (clip, chart_rect):
+                        draw_box_ticks (ctx, chart_rect, sec_w)
+                        draw_annotations (ctx, proc_tree, trace.times, chart_rect)
+                        draw_chart (ctx, IO_COLOR, True, chart_rect, \
+                                    [(sample.time, sample.util) for sample in trace.disk_stats], \
+                                    proc_tree, None)
+
+                # render disk throughput
+                max_sample = max (trace.disk_stats, key = lambda s: s.tput)
+                if clip_visible (clip, chart_rect):
+                        draw_chart (ctx, DISK_TPUT_COLOR, False, chart_rect, \
+                                    [(sample.time, sample.tput) for sample in trace.disk_stats], \
+                                    proc_tree, None)
+
+                pos_x = off_x + ((max_sample.time - proc_tree.start_time) * w / proc_tree.duration)
+
+                shift_x, shift_y = -20, 20
+                if (pos_x < off_x + 245):
+                        shift_x, shift_y = 5, 40
+
+                label = "%dMB/s" % round ((max_sample.tput) / 1024.0)
+                draw_text (ctx, label, DISK_TPUT_COLOR, pos_x + shift_x, curr_y + shift_y)
+
+                curr_y = curr_y + 30 + bar_h
 
         # render mem usage
         chart_rect = (off_x, curr_y+30, w, meminfo_bar_h)