#!/usr/bin/dtrace -s
#pragma D option quiet

BEGIN
{
        printf("Tracing... Hit Ctrl-c to end ,\n");

        r = 0;
        w = 0;
        bytes["read"] = 0;
        bytes["write"] = 0;

}





syscall::read:entry
/execname == "iozone" & r == 0 / {
        time_start_ns[probefunc] = timestamp;
        r = 1;

}
syscall::write:entry
/execname == "iozone" & w == 0 / {
        time_start_ns[probefunc] = timestamp;
        w = 1;

}

syscall::read:return,
syscall::write:return
/execname == "iozone" & time_start_ns[probefunc] != 0/ {
        /*
        timestamp :: nanoseconds
        ns = nanoseconds; us = microseconds; ms = milliseconds
        1 ns == 1,000 us == 1,000,000ms
        */

        time_finish_ns[probefunc] = timestamp;
}

syscall::read:entry,syscall::write:entry /execname == "iozone"/ {

        bytes[probefunc] = bytes[probefunc] + arg2;
        printf("At %Y file %s by %d bytes\n", walltimestamp,  probefunc, arg2);

        @[probefunc] = count();
}

END
{
        time_ns_write = time_finish_ns["write"] - time_start_ns["write"];
        time_ns_read = time_finish_ns["read"] - time_start_ns["read"];

        byte_second_write = ((bytes["write"] * 1000000000) / time_ns_write) / 1000;
        byte_second_read  = ((bytes["read"]  * 1000000000) / time_ns_read) / 1000;

        printf("        %d %7d %d %7d\n", bytes["read"], time_ns_read, bytes["write"], time_ns_write);
        printf("        %d %d\n", byte_second_write, byte_second_read);

        printf("        %-16s %7s\n", "SYSCALL", "COUNT");
        printa("        %-16s %@7d %@7d\n", @ );
}