Frederic Weisbecker | fb52607 | 2008-11-25 21:07:04 +0100 | [diff] [blame] | 1 | /* |
| 2 | * |
| 3 | * Function graph tracer. |
| 4 | * Copyright (c) 2008 Frederic Weisbecker <fweisbec@gmail.com> |
| 5 | * Mostly borrowed from function tracer which |
| 6 | * is Copyright (c) Steven Rostedt <srostedt@redhat.com> |
| 7 | * |
| 8 | */ |
| 9 | #include <linux/debugfs.h> |
| 10 | #include <linux/uaccess.h> |
| 11 | #include <linux/ftrace.h> |
| 12 | #include <linux/fs.h> |
| 13 | |
| 14 | #include "trace.h" |
| 15 | |
Frederic Weisbecker | 287b6e6 | 2008-11-26 00:57:25 +0100 | [diff] [blame] | 16 | #define TRACE_GRAPH_INDENT 2 |
Frederic Weisbecker | fb52607 | 2008-11-25 21:07:04 +0100 | [diff] [blame] | 17 | |
| 18 | #define TRACE_GRAPH_PRINT_OVERRUN 0x1 |
| 19 | static struct tracer_opt trace_opts[] = { |
| 20 | /* Display overruns or not */ |
| 21 | { TRACER_OPT(overrun, TRACE_GRAPH_PRINT_OVERRUN) }, |
| 22 | { } /* Empty entry */ |
| 23 | }; |
| 24 | |
| 25 | static struct tracer_flags tracer_flags = { |
| 26 | .val = 0, /* Don't display overruns by default */ |
| 27 | .opts = trace_opts |
| 28 | }; |
| 29 | |
Frederic Weisbecker | 287b6e6 | 2008-11-26 00:57:25 +0100 | [diff] [blame] | 30 | /* pid on the last trace processed */ |
| 31 | static pid_t last_pid = -1; |
Frederic Weisbecker | fb52607 | 2008-11-25 21:07:04 +0100 | [diff] [blame] | 32 | |
| 33 | static int graph_trace_init(struct trace_array *tr) |
| 34 | { |
Steven Rostedt | 660c7f9 | 2008-11-26 00:16:26 -0500 | [diff] [blame^] | 35 | int cpu, ret; |
| 36 | |
Frederic Weisbecker | fb52607 | 2008-11-25 21:07:04 +0100 | [diff] [blame] | 37 | for_each_online_cpu(cpu) |
| 38 | tracing_reset(tr, cpu); |
| 39 | |
Steven Rostedt | 660c7f9 | 2008-11-26 00:16:26 -0500 | [diff] [blame^] | 40 | ret = register_ftrace_graph(&trace_graph_return, |
Frederic Weisbecker | 287b6e6 | 2008-11-26 00:57:25 +0100 | [diff] [blame] | 41 | &trace_graph_entry); |
Steven Rostedt | 660c7f9 | 2008-11-26 00:16:26 -0500 | [diff] [blame^] | 42 | if (ret) |
| 43 | return ret; |
| 44 | tracing_start_cmdline_record(); |
| 45 | |
| 46 | return 0; |
Frederic Weisbecker | fb52607 | 2008-11-25 21:07:04 +0100 | [diff] [blame] | 47 | } |
| 48 | |
| 49 | static void graph_trace_reset(struct trace_array *tr) |
| 50 | { |
Steven Rostedt | 660c7f9 | 2008-11-26 00:16:26 -0500 | [diff] [blame^] | 51 | tracing_stop_cmdline_record(); |
| 52 | unregister_ftrace_graph(); |
Frederic Weisbecker | fb52607 | 2008-11-25 21:07:04 +0100 | [diff] [blame] | 53 | } |
| 54 | |
Frederic Weisbecker | 287b6e6 | 2008-11-26 00:57:25 +0100 | [diff] [blame] | 55 | /* If the pid changed since the last trace, output this event */ |
| 56 | static int verif_pid(struct trace_seq *s, pid_t pid) |
| 57 | { |
Steven Rostedt | 660c7f9 | 2008-11-26 00:16:26 -0500 | [diff] [blame^] | 58 | char *comm; |
| 59 | |
Frederic Weisbecker | 287b6e6 | 2008-11-26 00:57:25 +0100 | [diff] [blame] | 60 | if (last_pid != -1 && last_pid == pid) |
| 61 | return 1; |
| 62 | |
| 63 | last_pid = pid; |
Steven Rostedt | 660c7f9 | 2008-11-26 00:16:26 -0500 | [diff] [blame^] | 64 | comm = trace_find_cmdline(pid); |
| 65 | |
| 66 | return trace_seq_printf(s, "\n------------8<---------- thread %s-%d" |
Frederic Weisbecker | 287b6e6 | 2008-11-26 00:57:25 +0100 | [diff] [blame] | 67 | " ------------8<----------\n\n", |
Steven Rostedt | 660c7f9 | 2008-11-26 00:16:26 -0500 | [diff] [blame^] | 68 | comm, pid); |
Frederic Weisbecker | 287b6e6 | 2008-11-26 00:57:25 +0100 | [diff] [blame] | 69 | } |
| 70 | |
| 71 | static enum print_line_t |
| 72 | print_graph_entry(struct ftrace_graph_ent *call, struct trace_seq *s, |
| 73 | struct trace_entry *ent) |
| 74 | { |
| 75 | int i; |
| 76 | int ret; |
| 77 | |
| 78 | if (!verif_pid(s, ent->pid)) |
| 79 | return TRACE_TYPE_PARTIAL_LINE; |
| 80 | |
| 81 | for (i = 0; i < call->depth * TRACE_GRAPH_INDENT; i++) { |
| 82 | ret = trace_seq_printf(s, " "); |
| 83 | if (!ret) |
| 84 | return TRACE_TYPE_PARTIAL_LINE; |
| 85 | } |
| 86 | |
| 87 | ret = seq_print_ip_sym(s, call->func, 0); |
| 88 | if (!ret) |
| 89 | return TRACE_TYPE_PARTIAL_LINE; |
| 90 | |
| 91 | ret = trace_seq_printf(s, "() {\n"); |
| 92 | if (!ret) |
| 93 | return TRACE_TYPE_PARTIAL_LINE; |
| 94 | return TRACE_TYPE_HANDLED; |
| 95 | } |
| 96 | |
| 97 | static enum print_line_t |
| 98 | print_graph_return(struct ftrace_graph_ret *trace, struct trace_seq *s, |
| 99 | struct trace_entry *ent) |
| 100 | { |
| 101 | int i; |
| 102 | int ret; |
| 103 | |
| 104 | if (!verif_pid(s, ent->pid)) |
| 105 | return TRACE_TYPE_PARTIAL_LINE; |
| 106 | |
| 107 | for (i = 0; i < trace->depth * TRACE_GRAPH_INDENT; i++) { |
| 108 | ret = trace_seq_printf(s, " "); |
| 109 | if (!ret) |
| 110 | return TRACE_TYPE_PARTIAL_LINE; |
| 111 | } |
| 112 | |
| 113 | ret = trace_seq_printf(s, "} "); |
| 114 | if (!ret) |
| 115 | return TRACE_TYPE_PARTIAL_LINE; |
| 116 | |
| 117 | ret = trace_seq_printf(s, "%llu\n", trace->rettime - trace->calltime); |
| 118 | if (!ret) |
| 119 | return TRACE_TYPE_PARTIAL_LINE; |
| 120 | |
| 121 | if (tracer_flags.val & TRACE_GRAPH_PRINT_OVERRUN) { |
| 122 | ret = trace_seq_printf(s, " (Overruns: %lu)\n", |
| 123 | trace->overrun); |
| 124 | if (!ret) |
| 125 | return TRACE_TYPE_PARTIAL_LINE; |
| 126 | } |
| 127 | return TRACE_TYPE_HANDLED; |
| 128 | } |
Frederic Weisbecker | fb52607 | 2008-11-25 21:07:04 +0100 | [diff] [blame] | 129 | |
| 130 | enum print_line_t |
| 131 | print_graph_function(struct trace_iterator *iter) |
| 132 | { |
| 133 | struct trace_seq *s = &iter->seq; |
| 134 | struct trace_entry *entry = iter->ent; |
Frederic Weisbecker | fb52607 | 2008-11-25 21:07:04 +0100 | [diff] [blame] | 135 | |
Frederic Weisbecker | 287b6e6 | 2008-11-26 00:57:25 +0100 | [diff] [blame] | 136 | switch (entry->type) { |
| 137 | case TRACE_GRAPH_ENT: { |
| 138 | struct ftrace_graph_ent_entry *field; |
Frederic Weisbecker | fb52607 | 2008-11-25 21:07:04 +0100 | [diff] [blame] | 139 | trace_assign_type(field, entry); |
Frederic Weisbecker | 287b6e6 | 2008-11-26 00:57:25 +0100 | [diff] [blame] | 140 | return print_graph_entry(&field->graph_ent, s, entry); |
Frederic Weisbecker | fb52607 | 2008-11-25 21:07:04 +0100 | [diff] [blame] | 141 | } |
Frederic Weisbecker | 287b6e6 | 2008-11-26 00:57:25 +0100 | [diff] [blame] | 142 | case TRACE_GRAPH_RET: { |
| 143 | struct ftrace_graph_ret_entry *field; |
| 144 | trace_assign_type(field, entry); |
| 145 | return print_graph_return(&field->ret, s, entry); |
| 146 | } |
| 147 | default: |
| 148 | return TRACE_TYPE_UNHANDLED; |
| 149 | } |
Frederic Weisbecker | fb52607 | 2008-11-25 21:07:04 +0100 | [diff] [blame] | 150 | } |
| 151 | |
| 152 | static struct tracer graph_trace __read_mostly = { |
| 153 | .name = "function-graph", |
| 154 | .init = graph_trace_init, |
| 155 | .reset = graph_trace_reset, |
| 156 | .print_line = print_graph_function, |
| 157 | .flags = &tracer_flags, |
| 158 | }; |
| 159 | |
| 160 | static __init int init_graph_trace(void) |
| 161 | { |
| 162 | return register_tracer(&graph_trace); |
| 163 | } |
| 164 | |
| 165 | device_initcall(init_graph_trace); |