perf_helpers.h File Reference

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Data Structures
struct	ip_event
struct	lost_event
union	perf_sample_event_t

Functions
static long	sys_perf_event_open (struct perf_event_attr *hw_event, pid_t pid, int cpu, int group_fd, unsigned long flags)
static unsigned long long	mmap_read_self (void *addr, unsigned long long *en, unsigned long long *ru)
static uint64_t	mmap_read_head (pe_event_info_t *pe)
static void	mmap_write_tail (pe_event_info_t *pe, uint64_t tail)
static void	mmap_read (int cidx, ThreadInfo_t **thr, pe_event_info_t *pe, int profile_index)

Function Documentation

mmap_read()

static void mmap_read ( int  cidx, ThreadInfo_t **  thr, pe_event_info_t *  pe, int  profile_index  )

static

Definition at line 223 of file perf_helpers.h.

{
    uint64_t head = mmap_read_head( pe );
    uint64_t old = pe->tail;
    unsigned char *data = ((unsigned char*)pe->mmap_buf) + getpagesize();
    int diff;

    diff = head - old;
    if ( diff < 0 ) {
        SUBDBG( "WARNING: failed to keep up with mmap data. head = %" PRIu64
            ",  tail = %" PRIu64 ". Discarding samples.\n", head, old );
        /* head points to a known good entry, start there. */
        old = head;
    }

    for( ; old != head; ) {
        perf_sample_event_t *event = ( perf_sample_event_t * )& data[old & pe->mask];
        perf_sample_event_t event_copy;
        size_t size = event->header.size;

        /* Event straddles the mmap boundary -- header should always */
        /* be inside due to u64 alignment of output.                 */
        if ( ( old & pe->mask ) + size != ( ( old + size ) & pe->mask ) ) {
            uint64_t offset = old;
            uint64_t len = min( sizeof ( *event ), size ), cpy;
            void *dst = &event_copy;

            do {
                cpy = min( pe->mask + 1 - ( offset & pe->mask ), len );
                memcpy( dst, &data[offset & pe->mask], cpy );
                offset += cpy;
                dst = ((unsigned char*)dst) + cpy;
                len -= cpy;
            } while ( len );

            event = &event_copy;
        }
        old += size;

        SUBDBG( "event->type = %08x\n", event->header.type );
        SUBDBG( "event->size = %d\n", event->header.size );

        switch ( event->header.type ) {
            case PERF_RECORD_SAMPLE:
                _papi_hwi_dispatch_profile( ( *thr )->running_eventset[cidx],
                    ( caddr_t ) ( unsigned long ) event->ip.ip,
                    0, profile_index );
                break;

            case PERF_RECORD_LOST:
                SUBDBG( "Warning: because of a mmap buffer overrun, %" PRId64
                    " events were lost.\n"
                    "Loss was recorded when counter id %#"PRIx64
                    " overflowed.\n", event->lost.lost, event->lost.id );
                break;
            default:
                SUBDBG( "Error: unexpected header type - %d\n",
                    event->header.type );
                break;
        }
    }

    pe->tail = old;
    mmap_write_tail( pe, old );
}

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mmap_read_head()

static uint64_t mmap_read_head ( pe_event_info_t *  pe )

static

Definition at line 179 of file perf_helpers.h.

{
    struct perf_event_mmap_page *pc = pe->mmap_buf;
    int head;

    if ( pc == NULL ) {
        PAPIERROR( "perf_event_mmap_page is NULL" );
        return 0;
    }

    head = pc->data_head;
    rmb();

    return head;
}

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mmap_read_self()

static unsigned long long mmap_read_self ( void *  addr, unsigned long long *  en, unsigned long long *  ru  )

inlinestatic

Definition at line 158 of file perf_helpers.h.

                                             {

    (void)addr;

    *en=0;
    *ru=0;

    return (unsigned long long)(-1);
}

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mmap_write_tail()

static void mmap_write_tail ( pe_event_info_t *  pe, uint64_t  tail  )

static

Definition at line 196 of file perf_helpers.h.

{
    struct perf_event_mmap_page *pc = pe->mmap_buf;

    /* ensure all reads are done before we write the tail out. */
    pc->data_tail = tail;
}

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sys_perf_event_open()

static long sys_perf_event_open ( struct perf_event_attr *  hw_event, pid_t  pid, int  cpu, int  group_fd, unsigned long  flags  )

static

Definition at line 21 of file perf_helpers.h.

{
    int ret;

    ret = syscall( __NR_perf_event_open,
            hw_event, pid, cpu, group_fd, flags );

    return ret;
}

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