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tracing: have event_trace_printk use static tracer 

Impact: speed up on event tracing

The event_trace_printk is currently a wrapper function that calls
trace_vprintk. Because it uses a variable for the fmt it misses out
on the optimization of using the binary printk.

This patch makes event_trace_printk into a macro wrapper to use the
fmt as the same as the trace_printks.

Signed-off-by: Steven Rostedt <srostedt@redhat.com>
This commit is contained in:
Steven Rostedt 2009-03-12 14:19:25 -04:00
parent 828275574e
commit e9fb2b6d58
2 changed files with 17 additions and 10 deletions
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17
kernel/trace/trace.h
View File

@ -773,4 +773,21 @@ void event_trace_printk(unsigned long ip, const char *fmt, ...);
extern struct ftrace_event_call __start_ftrace_events[];
extern struct ftrace_event_call __stop_ftrace_events[];
extern const char *__start___trace_bprintk_fmt[];
extern const char *__stop___trace_bprintk_fmt[];
#define event_trace_printk(ip, fmt, args...) \
do { \
__trace_printk_check_format(fmt, ##args); \
tracing_record_cmdline(current); \
if (__builtin_constant_p(fmt)) { \
static const char *trace_printk_fmt \
__attribute__((section("__trace_printk_fmt"))) = \
__builtin_constant_p(fmt) ? fmt : NULL; \
\
__trace_bprintk(ip, trace_printk_fmt, ##args); \
} else \
__trace_printk(ip, fmt, ##args); \
} while (0)
#endif /* _LINUX_KERNEL_TRACE_H */

10
kernel/trace/trace_events.c
View File

@ -24,16 +24,6 @@ static DEFINE_MUTEX(event_mutex);
(unsigned long)event < (unsigned long)__stop_ftrace_events; \
event++)
void event_trace_printk(unsigned long ip, const char *fmt, ...)
{
va_list ap;
va_start(ap, fmt);
tracing_record_cmdline(current);
trace_vprintk(ip, task_curr_ret_stack(current), fmt, ap);
va_end(ap);
}
static void ftrace_clear_events(void)
{
struct ftrace_event_call *call = (void *)__start_ftrace_events;