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[profile] Add generic profiling infrastructure

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Signed-off-by: Michael Brown <mcb30@ipxe.org>
This commit is contained in:
Michael Brown
2014-04-23 17:43:18 +01:00
parent d36e814b8a
commit e5f6a9be38
10 changed files with 591 additions and 76 deletions
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108
src/include/ipxe/profile.h
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@@ -10,71 +10,85 @@
FILE_LICENCE ( GPL2_OR_LATER );
#include <stdint.h>
#include <bits/profile.h>
#include <ipxe/tables.h>
#ifdef NDEBUG
#define PROFILING 0
#else
#define PROFILING 1
#endif
/**
* A data structure for storing profiling information
*/
union profiler {
/** Timestamp (in CPU-specific "ticks") */
uint64_t timestamp;
/** Registers returned by rdtsc.
struct profiler {
/** Name */
const char *name;
/** Start timestamp */
uint64_t started;
/** Number of samples */
unsigned int count;
/** Mean sample value (scaled) */
unsigned long mean;
/** Mean sample value MSB
*
* This part should really be architecture-specific code.
* This is the highest bit set in the raw (unscaled) value
* (i.e. one less than would be returned by flsl(raw_mean)).
*/
struct {
uint32_t eax;
uint32_t edx;
} rdtsc;
unsigned int mean_msb;
/** Accumulated variance (scaled) */
unsigned long long accvar;
/** Accumulated variance MSB
*
* This is the highest bit set in the raw (unscaled) value
* (i.e. one less than would be returned by flsll(raw_accvar)).
*/
unsigned int accvar_msb;
};
/**
* Static per-object profiler, for use with simple_profile()
*/
static union profiler simple_profiler;
/** Profiler table */
#define PROFILERS __table ( struct profiler, "profilers" )
/** Declare a profiler */
#if PROFILING
#define __profiler __table_entry ( PROFILERS, 01 )
#else
#define __profiler
#endif
extern void profile_update ( struct profiler *profiler, unsigned long sample );
extern unsigned long profile_mean ( struct profiler *profiler );
extern unsigned long profile_variance ( struct profiler *profiler );
extern unsigned long profile_stddev ( struct profiler *profiler );
/**
* Perform profiling
* Start profiling
*
* @v profiler Profiler data structure
* @ret delta Elapsed ticks since last call to profile().
*
* Call profile() both before and after the code you wish to measure.
* The "after" call will return the measurement. For example:
*
* @code
*
* profile ( &profiler );
* ... do something here ...
* printf ( "It took %ld ticks to execute\n", profile ( &profiler ) );
*
* @endcode
* @v profiler Profiler
*/
static inline __attribute__ (( always_inline )) unsigned long
profile ( union profiler *profiler ) {
uint64_t last_timestamp = profiler->timestamp;
static inline __attribute__ (( always_inline )) void
profile_start ( struct profiler *profiler ) {
__asm__ __volatile__ ( "rdtsc" :
"=a" ( profiler->rdtsc.eax ),
"=d" ( profiler->rdtsc.edx ) );
return ( profiler->timestamp - last_timestamp );
/* If profiling is active then record start timestamp */
if ( PROFILING )
profiler->started = profile_timestamp();
}
/**
* Perform profiling
* Record profiling result
*
* @ret delta Elapsed ticks since last call to profile().
*
* When you only need one profiler, you can avoid the hassle of
* creating your own @c profiler data structure by using
* simple_profile() instead.
*
* simple_profile() is equivalent to profile(&simple_profiler), where
* @c simple_profiler is a @c profiler data structure that is static
* to each object which includes @c profile.h.
* @v profiler Profiler
*/
static inline __attribute__ (( always_inline )) unsigned long
simple_profile ( void ) {
return profile ( &simple_profiler );
static inline __attribute__ (( always_inline )) void
profile_stop ( struct profiler *profiler ) {
uint64_t ended;
/* If profiling is active then record end timestamp and update stats */
if ( PROFILING ) {
ended = profile_timestamp();
profile_update ( profiler, ( ended - profiler->started ) );
}
}
#endif /* _IPXE_PROFILE_H */