Re: [uml-devel] uml responsivenes or "AS vs DEADLINE Scheduler on uml-host" - was: [uml-user] Network lags

[BlaisorBlade <bla...@ya...>]

Alle 20:33, venerd=EC 9 aprile 2004, roland ha scritto:
> Hi !
> I think i found an interesting "scheduling issue" which led me to switch
> the subject of the thread.

1) Well, you switched from AS to deadline and got a significant IO performa=
nce=20
improvement, which made UML faster since it was Disk-bound. The problem wit=
h=20
AS is that it uses an heuristic, which assumes sequential reads.

But "find /" is very seeky, so it is slow with AS. So if you remove this bg=
=20
thread, you should get significantly different results.

Also, AS has had some changes in later kernels, so you should probably upgr=
ade=20
your host kernel to the latest version. A security hole (a local exploit to=
=20
become root) has also been fixed after 2.6.0.

2) In your last email, you speak about hogging the UML CPU. If Jeff guessed=
=20
correctly what happens, then avoiding that UML is idle will decrease the=20
worst-case ping response times.

=2D-=20
Paolo Giarrusso, aka Blaisorblade
Linux registered user n. 292729