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perf_counter: add support for multi-instance counters
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Signed-off-by: Tero Salminen <[email protected]>
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@t-salminen
t-salminen committed Aug 28, 2024
1 parent 964328e commit 99aa239
Showing 1 changed file with 40 additions and 28 deletions.
68 changes: 40 additions & 28 deletions src/lib/perf/perf_counter.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -57,8 +57,9 @@

#include "perf_counter.h"

#define PERF_MAX_INSTANCE 10
#define PERF_SHMNAME_PREFIX "_perf_"
#define PERF_SHMNAME_STR PERF_SHMNAME_PREFIX "%s"
#define PERF_SHMNAME_STR PERF_SHMNAME_PREFIX "%s_%d"
#define PERF_SHMNAME_MAX NAME_MAX + 1

#ifndef CONFIG_FS_SHMFS_VFS_PATH
Expand All @@ -75,6 +76,7 @@ struct perf_ctr_header {
#else
char name[PERF_SHMNAME_MAX]; /**< counter name */
#endif
uint8_t instance; /**< counter instance */
};

/**
Expand Down Expand Up @@ -141,9 +143,9 @@ static size_t perf_shmsize(int fd)
return sb.st_size;
}

static int perf_shmname(char *shmname, const char *name, size_t size)
static int perf_shmname(char *shmname, const char *name, uint8_t instance, size_t size)
{
int ret = snprintf(shmname, size, PERF_SHMNAME_STR, name);
int ret = snprintf(shmname, size, PERF_SHMNAME_STR, name, instance);

if ((size_t)ret >= size) {
return -ENAMETOOLONG;
Expand Down Expand Up @@ -191,23 +193,32 @@ static void perf_reset_cb(perf_counter_t handle, void *arg)
perf_counter_t
perf_alloc(enum perf_counter_type type, const char *name)
{
perf_counter_t ctr;
perf_counter_t ctr = nullptr;
char shmname[PERF_SHMNAME_MAX];
int ret;
int fd;
int inst;

/* generate name for shmfs file */
ret = perf_shmname(shmname, name, sizeof(shmname));
/* Find first free instance number */
for (inst = 0; inst < PERF_MAX_INSTANCE; inst++) {
/* generate name for shmfs file and append instance number to it */
ret = perf_shmname(shmname, name, inst, sizeof(shmname));

if (ret < 0) {
PX4_ERR("failed to allocate perf counter %s", name);
return nullptr;
}
if (ret < 0) {
PX4_ERR("failed to allocate perf counter %s", name);
return nullptr;
}

/* try to allocate new shm object and map it */
ctr = nullptr;
fd = shm_open(shmname, O_CREAT | O_RDWR | O_EXCL, 0666);
/* Try to allocate new shm object. This will fail for multi-instance counters
* until unused instance is found */
fd = shm_open(shmname, O_CREAT | O_RDWR | O_EXCL, 0666);

if (fd >= 0) {
break;
}
}

/* map shm object */
if (fd >= 0) {
ret = ftruncate(fd, perf_size(type));

Expand All @@ -229,6 +240,7 @@ perf_alloc(enum perf_counter_type type, const char *name)
#else
strncpy(ctr->name, name, PERF_SHMNAME_MAX);
#endif
ctr->instance = inst;
}

return ctr;
Expand All @@ -242,8 +254,8 @@ perf_alloc_once(enum perf_counter_type type, const char *name)
char shmname[PERF_SHMNAME_MAX];
int ret;

/* generate name for shmfs file */
ret = perf_shmname(shmname, name, sizeof(shmname));
/* Generate name for shmfs file. Only the first instance of counter is searched */
ret = perf_shmname(shmname, name, 0, sizeof(shmname));

if (ret < 0) {
PX4_ERR("failed to allocate perf counter %s", name);
Expand Down Expand Up @@ -281,7 +293,7 @@ perf_free(perf_counter_t handle)
char shmname[PERF_SHMNAME_MAX];

/* should not fail, if object creation succeeded ? */
if (perf_shmname(shmname, handle->name, sizeof(shmname)) >= 0) {
if (perf_shmname(shmname, handle->name, handle->instance, sizeof(shmname)) >= 0) {
shm_unlink(shmname);
}

Expand Down Expand Up @@ -526,17 +538,17 @@ perf_print_counter(perf_counter_t handle)

switch (handle->type) {
case PC_COUNT:
PX4_INFO_RAW("%s: %" PRIu64 " events\n",
handle->name,
PX4_INFO_RAW("%d: %s: %" PRIu64 " events\n",
handle->instance, handle->name,
((struct perf_ctr_count *)handle)->event_count);
break;

case PC_ELAPSED: {
struct perf_ctr_elapsed *pce = (struct perf_ctr_elapsed *)handle;
float rms = sqrtf(pce->M2 / (pce->event_count - 1));
PX4_INFO_RAW("%s: %" PRIu64 " events, %" PRIu64 "us elapsed, %.2fus avg, min %" PRIu32 "us max %" PRIu32
PX4_INFO_RAW("%d: %s: %" PRIu64 " events, %" PRIu64 "us elapsed, %.2fus avg, min %" PRIu32 "us max %" PRIu32
"us %5.3fus rms\n",
handle->name,
handle->instance, handle->name,
pce->event_count,
pce->time_total,
(pce->event_count == 0) ? 0 : (double)pce->time_total / (double)pce->event_count,
Expand All @@ -550,8 +562,8 @@ perf_print_counter(perf_counter_t handle)
struct perf_ctr_interval *pci = (struct perf_ctr_interval *)handle;
float rms = sqrtf(pci->M2 / (pci->event_count - 1));

PX4_INFO_RAW("%s: %" PRIu64 " events, %.2fus avg, min %" PRIu32 "us max %" PRIu32 "us %5.3fus rms\n",
handle->name,
PX4_INFO_RAW("%d: %s: %" PRIu64 " events, %.2fus avg, min %" PRIu32 "us max %" PRIu32 "us %5.3fus rms\n",
handle->instance, handle->name,
pci->event_count,
(pci->event_count == 0) ? 0 : (double)(pci->time_last - pci->time_first) / (double)pci->event_count,
pci->time_least,
Expand All @@ -577,17 +589,17 @@ perf_print_counter_buffer(char *buffer, int length, perf_counter_t handle)

switch (handle->type) {
case PC_COUNT:
num_written = snprintf(buffer, length, "%s: %" PRIu64 " events",
handle->name,
num_written = snprintf(buffer, length, "%d: %s: %" PRIu64 " events",
handle->instance, handle->name,
((struct perf_ctr_count *)handle)->event_count);
break;

case PC_ELAPSED: {
struct perf_ctr_elapsed *pce = (struct perf_ctr_elapsed *)handle;
float rms = sqrtf(pce->M2 / (pce->event_count - 1));
num_written = snprintf(buffer, length,
"%s: %" PRIu64 " events, %" PRIu64 "us elapsed, %.2fus avg, min %" PRIu32 "us max %" PRIu32 "us %5.3fus rms",
handle->name,
"%d: %s: %" PRIu64 " events, %" PRIu64 "us elapsed, %.2fus avg, min %" PRIu32 "us max %" PRIu32 "us %5.3fus rms",
handle->instance, handle->name,
pce->event_count,
pce->time_total,
(pce->event_count == 0) ? 0 : (double)pce->time_total / (double)pce->event_count,
Expand All @@ -602,8 +614,8 @@ perf_print_counter_buffer(char *buffer, int length, perf_counter_t handle)
float rms = sqrtf(pci->M2 / (pci->event_count - 1));

num_written = snprintf(buffer, length,
"%s: %" PRIu64 " events, %.2f avg, min %" PRIu32 "us max %" PRIu32 "us %5.3fus rms",
handle->name,
"%d: %s: %" PRIu64 " events, %.2f avg, min %" PRIu32 "us max %" PRIu32 "us %5.3fus rms",
handle->instance, handle->name,
pci->event_count,
(pci->event_count == 0) ? 0 : (double)(pci->time_last - pci->time_first) / (double)pci->event_count,
pci->time_least,
Expand Down

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