DTrace language preview

1. Tracing read latency

a shebang, a pragma, probe descriptions, and an aggregation

horizon-dark

#!/usr/sbin/dtrace -s
/* trace slow reads */
#pragma D option quiet

syscall::read:entry
{
    self->start = timestamp;
}

syscall::read:return
/self->start/
{
    @counts[execname] = count();
    printf("%s took %d ns\n", execname, timestamp - self->start);
    self->start = 0;
}

atom-one-dark

#!/usr/sbin/dtrace -s
/* trace slow reads */
#pragma D option quiet

syscall::read:entry
{
    self->start = timestamp;
}

syscall::read:return
/self->start/
{
    @counts[execname] = count();
    printf("%s took %d ns\n", execname, timestamp - self->start);
    self->start = 0;
}

github-dark

#!/usr/sbin/dtrace -s
/* trace slow reads */
#pragma D option quiet

syscall::read:entry
{
    self->start = timestamp;
}

syscall::read:return
/self->start/
{
    @counts[execname] = count();
    printf("%s took %d ns\n", execname, timestamp - self->start);
    self->start = 0;
}

dracula

#!/usr/sbin/dtrace -s
/* trace slow reads */
#pragma D option quiet

syscall::read:entry
{
    self->start = timestamp;
}

syscall::read:return
/self->start/
{
    @counts[execname] = count();
    printf("%s took %d ns\n", execname, timestamp - self->start);
    self->start = 0;
}

nord

#!/usr/sbin/dtrace -s
/* trace slow reads */
#pragma D option quiet

syscall::read:entry
{
    self->start = timestamp;
}

syscall::read:return
/self->start/
{
    @counts[execname] = count();
    printf("%s took %d ns\n", execname, timestamp - self->start);
    self->start = 0;
}

github

#!/usr/sbin/dtrace -s
/* trace slow reads */
#pragma D option quiet

syscall::read:entry
{
    self->start = timestamp;
}

syscall::read:return
/self->start/
{
    @counts[execname] = count();
    printf("%s took %d ns\n", execname, timestamp - self->start);
    self->start = 0;
}

2. Process-scoped probes

the pid$target provider and positional arguments

horizon-dark

pid$target:::entry
{
    printf("entered %s\n", probefunc);
}

pid$target:::return
{
    printf("returned from %s\n", probefunc);
}

atom-one-dark

pid$target:::entry
{
    printf("entered %s\n", probefunc);
}

pid$target:::return
{
    printf("returned from %s\n", probefunc);
}

github-dark

pid$target:::entry
{
    printf("entered %s\n", probefunc);
}

pid$target:::return
{
    printf("returned from %s\n", probefunc);
}

dracula

pid$target:::entry
{
    printf("entered %s\n", probefunc);
}

pid$target:::return
{
    printf("returned from %s\n", probefunc);
}

nord

pid$target:::entry
{
    printf("entered %s\n", probefunc);
}

pid$target:::return
{
    printf("returned from %s\n", probefunc);
}

github

pid$target:::entry
{
    printf("entered %s\n", probefunc);
}

pid$target:::return
{
    printf("returned from %s\n", probefunc);
}

3. Aggregation functions

quantize and sum aggregations

horizon-dark

syscall:::entry
{
    @dist[probefunc] = quantize(timestamp);
    @total = sum(1);
}

atom-one-dark

syscall:::entry
{
    @dist[probefunc] = quantize(timestamp);
    @total = sum(1);
}

github-dark

syscall:::entry
{
    @dist[probefunc] = quantize(timestamp);
    @total = sum(1);
}

dracula

syscall:::entry
{
    @dist[probefunc] = quantize(timestamp);
    @total = sum(1);
}

nord

syscall:::entry
{
    @dist[probefunc] = quantize(timestamp);
    @total = sum(1);
}

github

syscall:::entry
{
    @dist[probefunc] = quantize(timestamp);
    @total = sum(1);
}