operf_stats.cpp

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#include <stdio.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>

#include "operf_stats.h"
#include "op_get_time.h"

unsigned long operf_stats[OPERF_MAX_STATS];

using namespace std;
void operf_print_stats(string sessiondir, char * starttime, bool throttled)
{
    string operf_log (sessiondir);
    int total_lost_samples = 0;

    operf_log.append("/samples/operf.log");
    FILE * fp = fopen(operf_log.c_str(), "a");
    if (!fp) {
        fprintf(stderr, "Unable to open %s file.\n", operf_log.c_str());
        return;
    }
    fprintf(fp, "\nProfiling started at %s", starttime);
    fprintf(fp, "Profiling stopped at %s", op_get_time());
    fprintf(fp, "\n-- OProfile/operf Statistics --\n");
    fprintf(fp, "Nr. non-backtrace samples: %lu\n", operf_stats[OPERF_SAMPLES]);
    fprintf(fp, "Nr. kernel samples: %lu\n", operf_stats[OPERF_KERNEL]);
    fprintf(fp, "Nr. user space samples: %lu\n", operf_stats[OPERF_PROCESS]);
    fprintf(fp, "Nr. samples lost due to sample address not in expected range for domain: %lu\n",
           operf_stats[OPERF_INVALID_CTX]);
    fprintf(fp, "Nr. lost kernel samples: %lu\n", operf_stats[OPERF_LOST_KERNEL]);
    fprintf(fp, "Nr. samples lost due to sample file open failure: %lu\n",
        operf_stats[OPERF_LOST_SAMPLEFILE]);
    fprintf(fp, "Nr. samples lost due to no permanent mapping: %lu\n",
        operf_stats[OPERF_LOST_NO_MAPPING]);
    fprintf(fp, "Nr. user context kernel samples lost due to no app info available: %lu\n",
           operf_stats[OPERF_NO_APP_KERNEL_SAMPLE]);
    fprintf(fp, "Nr. user samples lost due to no app info available: %lu\n",
           operf_stats[OPERF_NO_APP_USER_SAMPLE]);
    fprintf(fp, "Nr. backtraces skipped due to no file mapping: %lu\n",
           operf_stats[OPERF_BT_LOST_NO_MAPPING]);
    fprintf(fp, "Nr. hypervisor samples dropped due to address out-of-range: %lu\n",
           operf_stats[OPERF_LOST_INVALID_HYPERV_ADDR]);
    fprintf(fp, "Nr. samples lost reported by perf_events kernel: %lu\n",
           operf_stats[OPERF_RECORD_LOST_SAMPLE]);

    if (operf_stats[OPERF_RECORD_LOST_SAMPLE]) {
        fprintf(stderr, "\n\n * * * ATTENTION: The kernel lost %lu samples. * * *\n",
                operf_stats[OPERF_RECORD_LOST_SAMPLE]);
        fprintf(stderr, "Decrease the sampling rate to eliminate (or reduce) lost samples.\n");
    } else if (throttled) {
        fprintf(stderr, "* * * * WARNING: Profiling rate was throttled back by the kernel * * * *\n");
        fprintf(stderr, "The number of samples actually recorded is less than expected, but is\n");
        fprintf(stderr, "probably still statistically valid.  Decreasing the sampling rate is the\n");
        fprintf(stderr, "best option if you want to avoid throttling.\n");
    }

    // TODO: handle extended stats
    //operf_ext_print_stats();

    for (int i = OPERF_INDEX_OF_FIRST_LOST_STAT; i < OPERF_MAX_STATS; i++)
        total_lost_samples += operf_stats[i];

    if (total_lost_samples > (int)(OPERF_WARN_LOST_SAMPLES_THRESHOLD
                       * operf_stats[OPERF_SAMPLES]))
        fprintf(stderr, "\nSee the %s file for statistics about lost samples.\n", operf_log.c_str());

    fflush(fp);
    fclose(fp);
}