From mboxrd@z Thu Jan  1 00:00:00 1970
From: David Gibson <david@gibson.dropbear.id.au>
To: passt-dev@passt.top
Subject: Re: [PATCH] test/README: Requirements for socket buffer sizes and
 hardware performance events
Date: Thu, 01 Sep 2022 11:37:22 +1000
Message-ID: <YxAM0loaf+2NttLR@yekko>
In-Reply-To: <20220830200007.3065472-1-sbrivio@redhat.com>
MIME-Version: 1.0
Content-Type: multipart/mixed; boundary="===============5341565262757826192=="

--===============5341565262757826192==
Content-Type: text/plain; charset="utf-8"
Content-Transfer-Encoding: quoted-printable

On Tue, Aug 30, 2022 at 10:00:07PM +0200, Stefano Brivio wrote:
> Performance tests use iperf3(1) with large windows, and these sysctl
> entries are needed to run them unmodified.
>=20
> The passt demo uses perf(1) to report syscall overhead, and that
> needs access to hardware performance counters for unprivileged
> users.
>=20
> Reported-by: David Gibson <david(a)gibson.dropbear.id.au>
> Signed-off-by: Stefano Brivio <sbrivio(a)redhat.com>

Reviewed-by: David Gibson <david(a)gibson.dropbear.id.au>

If I get time, I'll try to add something to skip these tests if the
host sysctl isn't set appropriately.

> ---
>  test/README.md | 16 ++++++++++++++++
>  1 file changed, 16 insertions(+)
>=20
> diff --git a/test/README.md b/test/README.md
> index 581949a..72a4986 100644
> --- a/test/README.md
> +++ b/test/README.md
> @@ -47,6 +47,22 @@ Virtual machine images are built during test executions =
using
>  [mbuto](https://mbuto.lameexcu.se/), the shell script is sourced via _git_
>  as needed, so there's no need to actually install it.
> =20
> +### Kernel parameters
> +
> +Performance tests use iperf3 with rather large TCP receiving and sending
> +windows, to decrease the likelihood of iperf3 itself becoming the bottlene=
ck.
> +These values need to be allowed by the kernel of the host running the test=
s.
> +Example for /etc/sysctl.conf:
> +
> +  net.core.rmem_max =3D 134217728
> +  net.core.wmem_max =3D 134217728
> +
> +Further, the passt demo uses perf(1), relying on hardware events for perfo=
rmance
> +counters, to display syscall overhead. The kernel needs to allow unprivile=
ged
> +users to access these events. Suggested entry for /etc/sysctl.conf:
> +
> +  kernel.perf_event_paranoid =3D -1
> +
>  ### Special requirements for continuous integration and demo modes
> =20
>  Running the test suite as continuous integration or demo modes will record=
 the

--=20
David Gibson			| I'll have my music baroque, and my code
david AT gibson.dropbear.id.au	| minimalist, thank you.  NOT _the_ _other_
				| _way_ _around_!
http://www.ozlabs.org/~dgibson

--===============5341565262757826192==
Content-Type: application/pgp-signature
Content-Transfer-Encoding: base64
Content-Disposition: attachment; filename="signature.asc"
MIME-Version: 1.0
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--===============5341565262757826192==--