Re: select returning slow on RH 2.4.18-14 (RH 8.0) kernel.

Arjan van de Ven (arjanv@redhat.com)
13 Feb 2003 12:39:00 +0100


This is a MIME-formatted message. If you see this text it means that your
E-mail software does not support MIME-formatted messages.

--=_courier-17718-1045137750-0001-2
Content-Type: text/plain
Content-Transfer-Encoding: quoted-printable

On Thu, 2003-02-13 at 10:08, Ben Greear wrote:
> I've been doing some testing with RH 8.0 on an Ezra 800Mhz
> machine.
>=20
> Even when lightly loaded select() often returns 3-9 miliseconds slower
> than the timeout would suggest. I know select is not guaranteed to
> return with < 10ms accuracy, but with almost no load, shouldn't it
> at least return with 1ms accuracy on average?
no
the kernel.org kernels will return in multiple-of-10ms quantities due to
HZ having the value of 100.
2.4.18-14 (which is btw obsoleted by several security errata) has a HZ
value of 512 so will return in shorter quantities, EXCEPT when you
always try to wait exactly 10ms of course....

--=_courier-17718-1045137750-0001-2
Content-Type: application/pgp-signature; name="signature.asc"
Content-Transfer-Encoding: 7bit
Content-Description: This is a digitally signed message part

-----BEGIN PGP SIGNATURE-----
Version: GnuPG v1.2.1 (GNU/Linux)

iD8DBQA+S4PUxULwo51rQBIRAgwwAJ9UKBYIUHR2c+gFDS6LwlkMEkiQEQCfSLRh
f8IjlnoIEykfrNK67vTzqlc=
=ZzaC
-----END PGP SIGNATURE-----

--=_courier-17718-1045137750-0001-2--