From 6019e59489e288c1eb7276387ea45d8ceb69f6b2 Mon Sep 17 00:00:00 2001 From: Jamie Gennis Date: Wed, 21 Nov 2012 15:04:25 -0800 Subject: [PATCH] trace: Add an option to show tgids in trace output The tgids are tracked along side the saved_cmdlines tracking, and can be included in trace output by enabling the 'print-tgid' trace option. This is useful when doing post-processing of the trace data, as it allows events to be grouped by tgid. Change-Id: I52ed04c3a8ca7fddbb868b792ce5d21ceb76250e Signed-off-by: Jamie Gennis --- kernel/trace/trace.c | 98 +++++++++++++++++++++++++++++++++++-- kernel/trace/trace.h | 4 +- kernel/trace/trace_output.c | 14 +++++- 3 files changed, 110 insertions(+), 6 deletions(-) diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c index 87fb9801bd9e..225d450cd84d 100644 --- a/kernel/trace/trace.c +++ b/kernel/trace/trace.c @@ -1352,6 +1352,7 @@ void tracing_reset_all_online_cpus(void) #define SAVED_CMDLINES_DEFAULT 128 #define NO_CMDLINE_MAP UINT_MAX +static unsigned saved_tgids[SAVED_CMDLINES]; static arch_spinlock_t trace_cmdline_lock = __ARCH_SPIN_LOCK_UNLOCKED; struct saved_cmdlines_buffer { unsigned map_pid_to_cmdline[PID_MAX_DEFAULT+1]; @@ -1590,7 +1591,7 @@ static int trace_save_cmdline(struct task_struct *tsk) } set_cmdline(idx, tsk->comm); - + saved_tgids[idx] = tsk->tgid; arch_spin_unlock(&trace_cmdline_lock); return 1; @@ -1633,6 +1634,25 @@ void trace_find_cmdline(int pid, char comm[]) preempt_enable(); } +int trace_find_tgid(int pid) +{ + unsigned map; + int tgid; + + preempt_disable(); + arch_spin_lock(&trace_cmdline_lock); + map = map_pid_to_cmdline[pid]; + if (map != NO_CMDLINE_MAP) + tgid = saved_tgids[map]; + else + tgid = -1; + + arch_spin_unlock(&trace_cmdline_lock); + preempt_enable(); + + return tgid; +} + void tracing_record_cmdline(struct task_struct *tsk) { if (atomic_read(&trace_record_cmdline_disabled) || !tracing_is_on()) @@ -2583,6 +2603,13 @@ static void print_func_help_header(struct trace_buffer *buf, struct seq_file *m) "# | | | | |\n"); } +static void print_func_help_header_tgid(struct trace_buffer *buf, struct seq_file *m) +{ + print_event_info(buf, m); + seq_puts(m, "# TASK-PID TGID CPU# TIMESTAMP FUNCTION\n"); + seq_puts(m, "# | | | | | |\n"); +} + static void print_func_help_header_irq(struct trace_buffer *buf, struct seq_file *m) { print_event_info(buf, m); @@ -2595,6 +2622,18 @@ static void print_func_help_header_irq(struct trace_buffer *buf, struct seq_file "# | | | |||| | |\n"); } +static void print_func_help_header_irq_tgid(struct trace_buffer *buf, struct seq_file *m) +{ + print_event_info(buf, m); + seq_puts(m, "# _-----=> irqs-off\n"); + seq_puts(m, "# / _----=> need-resched\n"); + seq_puts(m, "# | / _---=> hardirq/softirq\n"); + seq_puts(m, "# || / _--=> preempt-depth\n"); + seq_puts(m, "# ||| / delay\n"); + seq_puts(m, "# TASK-PID TGID CPU# |||| TIMESTAMP FUNCTION\n"); + seq_puts(m, "# | | | | |||| | |\n"); +} + void print_trace_header(struct seq_file *m, struct trace_iterator *iter) { @@ -2907,9 +2946,15 @@ void trace_default_header(struct seq_file *m) } else { if (!(trace_flags & TRACE_ITER_VERBOSE)) { if (trace_flags & TRACE_ITER_IRQ_INFO) - print_func_help_header_irq(iter->trace_buffer, m); + if (trace_flags & TRACE_ITER_TGID) + print_func_help_header_irq_tgid(iter->trace_buffer, m); + else + print_func_help_header_irq(iter->trace_buffer, m); else - print_func_help_header(iter->trace_buffer, m); + if (trace_flags & TRACE_ITER_TGID) + print_func_help_header_tgid(iter->trace_buffer, m); + else + print_func_help_header(iter->trace_buffer, m); } } } @@ -4160,6 +4205,50 @@ static void trace_insert_enum_map(struct module *mod, trace_insert_enum_map_file(mod, start, len); } +static ssize_t +tracing_saved_tgids_read(struct file *file, char __user *ubuf, + size_t cnt, loff_t *ppos) +{ + char *file_buf; + char *buf; + int len = 0; + int pid; + int i; + + file_buf = kmalloc(SAVED_CMDLINES*(16+1+16), GFP_KERNEL); + if (!file_buf) + return -ENOMEM; + + buf = file_buf; + + for (i = 0; i < SAVED_CMDLINES; i++) { + int tgid; + int r; + + pid = map_cmdline_to_pid[i]; + if (pid == -1 || pid == NO_CMDLINE_MAP) + continue; + + tgid = trace_find_tgid(pid); + r = sprintf(buf, "%d %d\n", pid, tgid); + buf += r; + len += r; + } + + len = simple_read_from_buffer(ubuf, cnt, ppos, + file_buf, len); + + kfree(file_buf); + + return len; +} + +static const struct file_operations tracing_saved_tgids_fops = { + .open = tracing_open_generic, + .read = tracing_saved_tgids_read, + .llseek = generic_file_llseek, +}; + static ssize_t tracing_set_trace_read(struct file *filp, char __user *ubuf, size_t cnt, loff_t *ppos) @@ -6784,6 +6873,9 @@ init_tracer_tracefs(struct trace_array *tr, struct dentry *d_tracer) trace_create_file("trace_marker", 0220, d_tracer, tr, &tracing_mark_fops); + trace_create_file("saved_tgids", 0444, d_tracer, + tr, &tracing_saved_tgids_fops); + trace_create_file("trace_clock", 0644, d_tracer, tr, &trace_clock_fops); diff --git a/kernel/trace/trace.h b/kernel/trace/trace.h index 919d9d07686f..e1265f95457f 100644 --- a/kernel/trace/trace.h +++ b/kernel/trace/trace.h @@ -656,6 +656,7 @@ static inline void __trace_stack(struct trace_array *tr, unsigned long flags, extern cycle_t ftrace_now(int cpu); extern void trace_find_cmdline(int pid, char comm[]); +extern int trace_find_tgid(int pid); #ifdef CONFIG_DYNAMIC_FTRACE extern unsigned long ftrace_update_tot_cnt; @@ -970,7 +971,8 @@ extern int trace_get_user(struct trace_parser *parser, const char __user *ubuf, FUNCTION_FLAGS \ FGRAPH_FLAGS \ STACK_FLAGS \ - BRANCH_FLAGS + BRANCH_FLAGS \ + C(TGID, "print-tgid"), /* * By defining C, we can make TRACE_FLAGS a list of bit names diff --git a/kernel/trace/trace_output.c b/kernel/trace/trace_output.c index 282982195e09..a2fc60a74e27 100644 --- a/kernel/trace/trace_output.c +++ b/kernel/trace/trace_output.c @@ -526,11 +526,21 @@ int trace_print_context(struct trace_iterator *iter) unsigned long long t; unsigned long secs, usec_rem; char comm[TASK_COMM_LEN]; + int tgid; trace_find_cmdline(entry->pid, comm); - trace_seq_printf(s, "%16s-%-5d [%03d] ", - comm, entry->pid, iter->cpu); + trace_seq_printf(s, "%16s-%-5d ", comm, entry->pid); + + if (tr->trace_flags & TRACE_ITER_TGID) { + tgid = trace_find_tgid(entry->pid); + if (tgid < 0) + trace_seq_puts(s, "(-----) "); + else + trace_seq_printf(s, "(%5d) ", tgid); + } + + trace_seq_printf(s, "[%03d] ", iter->cpu); if (tr->trace_flags & TRACE_ITER_IRQ_INFO) trace_print_lat_fmt(s, entry); -- 2.34.1