Block IO size and latency tracing

biostats.bt

#!/usr/bin/env bpftrace

BEGIN {
    printf("Tracing block io, Ctrl-C to get result\n");
}

tracepoint:block:block_rq_issue / args->sector > 0 /
{
    @start[args->sector] = nsecs;
    @kbs[args->sector] = args->bytes / 1024;
}


tracepoint:block:block_rq_complete /args->sector > 0 && @start[args->sector] /
{
    $now = nsecs;
    $sector = args->sector;
    $s = @start[$sector];
    $lat = ($now - $s) / 1000000;
    delete(@start[$sector]);
    $k = @kbs[$sector];
    delete(@kbs[$sector]);
    @kbytes = hist($k);
    @latency_ms = hist($lat);
}

END {
    delete(@start);
    delete(@kbs);
}