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Date: Fri, 10 Oct 2008 15:02:49 +0200
From: "Frédéric Weisbecker" <fweisbec@...il.com>
To: "Ingo Molnar" <mingo@...e.hu>
Cc: "Arjan van de Ven" <arjan@...radead.org>,
"Steven Rostedt" <rostedt@...dmis.org>,
Linux-Kernel <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH 6/6] tracing/fastboot: Print ktime of sched events when boot tracing
2008/10/10 Frederic Weisbecker <fweisbec@...il.com>:
>
> When we use the boot tracer, we want the sched events to be printed with the
> same timestamp than initcall events.
> So we have to create a new type of entry which contains sched event attributes
> and the ktime of the creation of the entry.
> Then the output is handled by the boot tracer.
>
> Signed-off-by: Frederic Weisbecker <fweisbec@...il.com>
> CC: Steven Rostedt <rostedt@...dmis.org>
> CC: Arjan van de Ven <arjan@...radead.org>
> ---
> kernel/trace/trace.c | 107 ++++++++++++++++++++++++++++++++++++++++----
> kernel/trace/trace.h | 22 +++++++++
> kernel/trace/trace_boot.c | 96 ++++++++++++++++++++++++++++++++--------
> 3 files changed, 196 insertions(+), 29 deletions(-)
>
> diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c
> index acc21bb..4300521 100644
> --- a/kernel/trace/trace.c
> +++ b/kernel/trace/trace.c
> @@ -622,7 +622,7 @@ static void trace_save_cmdline(struct task_struct *tsk)
> spin_unlock(&trace_cmdline_lock);
> }
>
> -static char *trace_find_cmdline(int pid)
> +char *trace_find_cmdline(int pid)
> {
> char *cmdline = "<...>";
> unsigned map;
> @@ -774,12 +774,12 @@ __trace_special(void *__tr, void *__data,
> ftrace_trace_special(__tr, __data, arg1, arg2, arg3, preempt_count());
> }
>
> -void
> -tracing_sched_switch_trace(struct trace_array *tr,
> - struct trace_array_cpu *data,
> - struct task_struct *prev,
> - struct task_struct *next,
> - unsigned long flags, int pc)
> +static void
> +__tracing_sched_switch_trace(struct trace_array *tr,
> + struct trace_array_cpu *data,
> + struct task_struct *prev,
> + struct task_struct *next,
> + unsigned long flags, int pc)
> {
> struct ring_buffer_event *event;
> struct ctx_switch_entry *entry;
> @@ -803,13 +803,85 @@ tracing_sched_switch_trace(struct trace_array *tr,
> ftrace_trace_stack(tr, data, flags, 5, pc);
> }
>
> +static void
> +__tracing_sched_switch_boot_trace(struct trace_array *tr,
> + struct trace_array_cpu *data,
> + struct task_struct *prev,
> + struct task_struct *next,
> + unsigned long flags, int pc)
> +{
> + struct ring_buffer_event *event;
> + struct ctx_switch_boot_entry *entry;
> + unsigned long irq_flags;
> +
> + event = ring_buffer_lock_reserve(tr->buffer, sizeof(*entry),
> + &irq_flags);
> + if (!event)
> + return;
> + entry = ring_buffer_event_data(event);
> + tracing_generic_entry_update(&entry->ent, flags, pc);
> + entry->ent.type = TRACE_CTX_BOOT;
> + entry->prev_pid = prev->pid;
> + entry->prev_prio = prev->prio;
> + entry->prev_state = prev->state;
> + entry->next_pid = next->pid;
> + entry->next_prio = next->prio;
> + entry->next_state = next->state;
> + entry->next_cpu = task_cpu(next);
> + entry->time = ktime_get();
> + ring_buffer_unlock_commit(tr->buffer, event, irq_flags);
> +}
> +
> void
> -tracing_sched_wakeup_trace(struct trace_array *tr,
> +tracing_sched_switch_trace(struct trace_array *tr,
> struct trace_array_cpu *data,
> - struct task_struct *wakee,
> - struct task_struct *curr,
> + struct task_struct *prev,
> + struct task_struct *next,
> unsigned long flags, int pc)
> {
> + if (current_trace == &boot_tracer)
> + __tracing_sched_switch_boot_trace(tr, data, prev,
> + next, flags, pc);
> + else
> + __tracing_sched_switch_trace(tr, data, prev, next, flags, pc);
> +}
> +
> +static void
> +__tracing_sched_wakeup_boot_trace(struct trace_array *tr,
> + struct trace_array_cpu *data,
> + struct task_struct *wakee,
> + struct task_struct *curr,
> + unsigned long flags, int pc)
> +{
> + struct ring_buffer_event *event;
> + struct ctx_switch_boot_entry *entry;
> + unsigned long irq_flags;
> +
> + event = ring_buffer_lock_reserve(tr->buffer, sizeof(*entry),
> + &irq_flags);
> + if (!event)
> + return;
> + entry = ring_buffer_event_data(event);
> + tracing_generic_entry_update(&entry->ent, flags, pc);
> + entry->ent.type = TRACE_WAKE_BOOT;
> + entry->prev_pid = curr->pid;
> + entry->prev_prio = curr->prio;
> + entry->prev_state = curr->state;
> + entry->next_pid = wakee->pid;
> + entry->next_prio = wakee->prio;
> + entry->next_state = wakee->state;
> + entry->next_cpu = task_cpu(wakee);
> + entry->time = ktime_get();
> + ring_buffer_unlock_commit(tr->buffer, event, irq_flags);
> +}
> +
> +static void
> +__tracing_sched_wakeup_trace(struct trace_array *tr,
> + struct trace_array_cpu *data,
> + struct task_struct *wakee,
> + struct task_struct *curr,
> + unsigned long flags, int pc)
> +{
> struct ring_buffer_event *event;
> struct ctx_switch_entry *entry;
> unsigned long irq_flags;
> @@ -835,6 +907,21 @@ tracing_sched_wakeup_trace(struct trace_array *tr,
> }
>
> void
> +tracing_sched_wakeup_trace(struct trace_array *tr,
> + struct trace_array_cpu *data,
> + struct task_struct *wakee,
> + struct task_struct *curr,
> + unsigned long flags, int pc)
> +{
> +
> + if (current_trace == &boot_tracer)
> + __tracing_sched_wakeup_boot_trace(tr, data, wakee,
> + curr, flags, pc);
> + else
> + __tracing_sched_wakeup_trace(tr, data, wakee, curr, flags, pc);
> +}
> +
> +void
> ftrace_special(unsigned long arg1, unsigned long arg2, unsigned long arg3)
> {
> struct trace_array *tr = &global_trace;
> diff --git a/kernel/trace/trace.h b/kernel/trace/trace.h
> index d45a3cd..b7fe667 100644
> --- a/kernel/trace/trace.h
> +++ b/kernel/trace/trace.h
> @@ -22,6 +22,8 @@ enum trace_type {
> TRACE_MMIO_RW,
> TRACE_MMIO_MAP,
> TRACE_BOOT,
> + TRACE_CTX_BOOT,
> + TRACE_WAKE_BOOT,
>
> __TRACE_LAST_TYPE
> };
> @@ -66,6 +68,24 @@ struct ctx_switch_entry {
> };
>
> /*
> + * Context switch trace entry with ktime timestamp.
> + * It is required for the boot tracer which needs unified
> + * time measure between initcalls and sched events.
> + */
> +
> +struct ctx_switch_boot_entry {
> + struct trace_entry ent;
> + unsigned int prev_pid;
> + unsigned char prev_prio;
> + unsigned char prev_state;
> + unsigned int next_pid;
> + unsigned char next_prio;
> + unsigned char next_state;
> + unsigned int next_cpu;
> + ktime_t time;
> +};
> +
> +/*
> * Special (free-form) trace entry:
> */
> struct special_entry {
> @@ -218,6 +238,7 @@ extern void __ftrace_bad_type(void);
> IF_ASSIGN(var, ent, struct trace_mmiotrace_map, \
> TRACE_MMIO_MAP); \
> IF_ASSIGN(var, ent, struct trace_boot, TRACE_BOOT); \
> + IF_ASSIGN(var, ent, struct ctx_switch_boot_entry, 0); \
> __ftrace_bad_type(); \
> } while (0)
>
> @@ -392,6 +413,7 @@ extern ssize_t trace_seq_to_user(struct trace_seq *s, char __user *ubuf,
> size_t cnt);
> extern long ns2usecs(cycle_t nsec);
> extern int trace_vprintk(unsigned long ip, const char *fmt, va_list args);
> +extern char *trace_find_cmdline(int pid);
>
> extern unsigned long trace_flags;
>
> diff --git a/kernel/trace/trace_boot.c b/kernel/trace/trace_boot.c
> index 6bbc879..11e6573 100644
> --- a/kernel/trace/trace_boot.c
> +++ b/kernel/trace/trace_boot.c
> @@ -14,6 +14,7 @@
>
> static struct trace_array *boot_trace;
> static bool pre_initcalls_finished;
> +static const char state_to_char[] = TASK_STATE_TO_CHAR_STR;
>
> /* Tells the boot tracer that the pre_smp_initcalls are finished.
> * So we are ready .
> @@ -71,34 +72,91 @@ static enum print_line_t initcall_print_line(struct trace_iterator *iter)
> struct timespec calltime = ktime_to_timespec(it->calltime);
> struct timespec rettime = ktime_to_timespec(it->rettime);
>
> - if (entry->type == TRACE_BOOT) {
> - ret = trace_seq_printf(s, "[%5ld.%09ld] calling %s @ %i\n",
> - calltime.tv_sec,
> - calltime.tv_nsec,
> - it->func, it->caller);
> - if (!ret)
> - return TRACE_TYPE_PARTIAL_LINE;
> -
> - ret = trace_seq_printf(s, "[%5ld.%09ld] initcall %s "
> - "returned %d after %lld msecs\n",
> - rettime.tv_sec,
> - rettime.tv_nsec,
> - it->func, it->result, it->duration);
> -
> - if (!ret)
> - return TRACE_TYPE_PARTIAL_LINE;
> - return TRACE_TYPE_HANDLED;
> - }
> + ret = trace_seq_printf(s, "[%5ld.%09ld] calling %s @ %i\n",
> + calltime.tv_sec,
> + calltime.tv_nsec,
> + it->func, it->caller);
> + if (!ret)
> + return TRACE_TYPE_PARTIAL_LINE;
> +
> + ret = trace_seq_printf(s, "[%5ld.%09ld] initcall %s "
> + "returned %d after %lld msecs\n",
> + rettime.tv_sec,
> + rettime.tv_nsec,
> + it->func, it->result, it->duration);
> +
> + if (!ret)
> + return TRACE_TYPE_PARTIAL_LINE;
> + return TRACE_TYPE_HANDLED;
> +
> +}
> +
> +static enum print_line_t sched_switch_print_line(struct trace_iterator *iter)
> +{
> + int ret;
> + struct trace_entry *entry = iter->ent;
> + struct ctx_switch_boot_entry *field;
> + struct trace_seq *s = &iter->seq;
> + struct timespec time;
> + int S, T;
> + char *comm;
> +
> + trace_assign_type(field, entry);
> + time = ktime_to_timespec(field->time);
> +
> + comm = trace_find_cmdline(iter->ent->pid);
> +
> + ret = trace_seq_printf(s, "[%5ld.%09ld] ",
> + time.tv_sec,
> + time.tv_nsec);
> +
> + ret = trace_seq_printf(s, "%16s-%-5d ", comm, entry->pid);
> + if (!ret)
> + return TRACE_TYPE_PARTIAL_LINE;
> + ret = trace_seq_printf(s, "[%03d] ", iter->cpu);
> + if (!ret)
> + return TRACE_TYPE_PARTIAL_LINE;
> +
> + if (!ret)
> + return TRACE_TYPE_PARTIAL_LINE;
> +
> + S = field->prev_state < sizeof(state_to_char) ?
> + state_to_char[field->prev_state] : 'X';
> + T = field->next_state < sizeof(state_to_char) ?
> + state_to_char[field->next_state] : 'X';
> + ret = trace_seq_printf(s, " %5d:%3d:%c %s [%03d] %5d:%3d:%c\n",
> + field->prev_pid,
> + field->prev_prio,
> + S,
> + entry->type == TRACE_CTX ? "==>" : " +",
> + field->next_cpu,
> + field->next_pid,
> + field->next_prio,
> + T);
> + if (!ret)
> + return TRACE_TYPE_PARTIAL_LINE;
> + return TRACE_TYPE_HANDLED;
> +}
> +
> +static enum print_line_t boot_trace_print_line(struct trace_iterator *iter)
> +{
> + struct trace_entry *entry = iter->ent;
> +
> + if (entry->type == TRACE_BOOT)
> + return initcall_print_line(iter);
> + if (entry->type == TRACE_CTX_BOOT || entry->type == TRACE_WAKE_BOOT)
> + return sched_switch_print_line(iter);
> return TRACE_TYPE_UNHANDLED;
> }
>
> +
> struct tracer boot_tracer __read_mostly =
> {
> .name = "initcall",
> .init = boot_trace_init,
> .reset = reset_boot_trace,
> .ctrl_update = boot_trace_ctrl_update,
> - .print_line = initcall_print_line,
> + .print_line = boot_trace_print_line,
> };
>
> void trace_boot(struct boot_trace *it, initcall_t fn)
I forgot to say that a lot of this code is borrowed from trace.c
(print_trace_fmt function) which is copyright...a lot of people :)
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