Re: CONFIG_NO_HZ causing poor console responsiveness
From: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Date: 2010-07-02 05:47:32
From: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Date: 2010-07-02 05:47:32
On Tue, 2010-06-29 at 14:54 -0500, Timur Tabi wrote:
I'm adding support for a new e500-based board (the P1022DS), and in the process I've discovered that enabling CONFIG_NO_HZ (Tickless System / Dynamic Ticks) causes significant responsiveness problems on the serial console. When I type on the console, I see delays of up to a half-second for almost every character. It acts as if there's a background process eating all the CPU. I don't have time to debug this thoroughly at the moment. The problem occurs in the latest kernel, but it appears not to occur in 2.6.32. Has anyone else seen anything like this?
I noticed that on the bimini with 2.6.35-rc* though I didn't get to track it down yet. Cheers, Ben.