Re: Busy-wait delay in qmail 1.03 after upgrading to Linux 2.6

From: Peter Maas
Date: Tue Jan 20 2004 - 00:53:28 EST


Re: Haakon Riiser
>I think I've been able to create a simple test program that
>demonstrates the bug I encountered with Qmail.

I've compiled and tested the code you posted, i thought that i would add
that renicing the LISTENER processes shows some interesting effects.

at nice 0 the writer spits out about 40 writes under .01 ms, then 3 to 5
writes at 97+ ms, after about 3 minutes its starts to get more random.
at nice -1 the writer spits out about 40 writes under .01 ms, then about 40
writes at 97+ ms, kept this cycle for over 10 minutes.
at nice 1 the writer spits out a few hundred writes under .01 ms, and
occasionally one at 97+ ms.

same effect if elevator=deadline

This thread caught my intrest because I run qmail on this box.

Peter Maas

Pentium II - 400MHz 128MB PC100
kernel-2.6.1-1.126 from http://people.redhat.com/arjanv/2.6/
(not subscribed - reads archives)

-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/