Re: [PATCH] dtrace probes for memory manager

Zdenek Kotala <Zdenek.Kotala@Sun.COM> writes:

> [...]
> +    header = (StandardChunkHeader *)
> +        ((char *) ret - STANDARDCHUNKHEADERSIZE);
> +
> +//    TRACE_POSTGRESQL_MCXT_ALLOC(context->name, context, size, header->size, true);
> +
> [...]

If the dormant overhead of these probes is measured or suspected to be
excessive, consider using the dtrace-generated per-probe foo_ENABLED()
conditional, or a postgres configuration global thusly:
  if (__builtin_expect(TRACE_POSTGRESQL_MCXT_ALLOC_ENABLED(), 0))     TRACE_POSTGRESQL_MCXT_ALLOC(...);

so that the whole instrumentation parameter setup/call can be placed
out of the hot line with gcc -freorder-blocks.

- FChE