Re: [DTrace-devel] [PATCH] test: Increase syscall entry timeout

[Nick Alcock <nick.alcock@oracle.com>]

On 22 Jan 2026, eugene loh outgrape:

> From: Eugene Loh <eugene.loh@oracle.com>
>
> The run time for this test seems twice as long for aarch64 as for
> x86_64.  Further, the run time seems to have jumped significantly from
> kernel 5.15 to 6.12 and then again to kernel 6.18.  E.g.,

Ew.

>                   x86_64     aarch64
>     5.15          7 secs     18 secs
>     6.12         12 secs     33 secs
>     6.18         22 secs     54 secs
>
> Looking at a run on the 6.18 aarch64 system, the time is basically
> spent in the dtrace_close() call to dt_probe_detach_all(), which does:
>
>     for (prp = ...)
>         prp->prov->impl->detach(dtp, prp);
>
> Then, dt_tp_probe_detach() calls dt_tp_detach(), which does:
>
>     close(tpp->fd);
>
> This close() averages over 0.1 secs.  For hundreds of syscall probes,
> we get nearly a minute of run time, exceeding the default test timeout.

Sounds like another O(n^2) crept back in somewhere in the kernel :(

> For the time being, increase the timeout on this test.
>
> Signed-off-by: Eugene Loh <eugene.loh@oracle.com>

Reviewed-by: Nick Alcock <nick.alcock@oracle.com>