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Date: Sat, 14 Apr 2007 19:54:33 +0200 From: Ingo Molnar <mingo@...e.hu> To: "Eric W. Biederman" <ebiederm@...ssion.com> Cc: Willy Tarreau <w@....eu>, Nick Piggin <npiggin@...e.de>, linux-kernel@...r.kernel.org, Linus Torvalds <torvalds@...ux-foundation.org>, Andrew Morton <akpm@...ux-foundation.org>, Con Kolivas <kernel@...ivas.org>, Mike Galbraith <efault@....de>, Arjan van de Ven <arjan@...radead.org>, Thomas Gleixner <tglx@...utronix.de>, Jiri Slaby <jirislaby@...il.com>, Alan Cox <alan@...rguk.ukuu.org.uk> Subject: Re: [Announce] [patch] Modular Scheduler Core and Completely Fair Scheduler [CFS] * Eric W. Biederman <ebiederm@...ssion.com> wrote: > > Thinking about it, I don't know if there are calls to schedule() > > while switching from tty1 to tty2. Alt-F2 had no effect anymore, and > > "chvt 2" simply blocked. It would have been possible that a > > schedule() call somewhere got starved due to the load, I don't know. > > It looks like there is a call to schedule_work. so this goes over keventd, right? > There are two pieces of the path. If you are switching in and out of a > tty controlled by something like X. User space has to grant > permission before the operation happens. Where there isn't a gate > keeper I know it is cheaper but I don't know by how much, I suspect > there is still a schedule happening in there. Could keventd perhaps be starved? Willy, to exclude this possibility, could you perhaps chrt keventd to RT priority? If events/0 is PID 5 then the command to set it to SCHED_FIFO:50 would be: chrt -f -p 50 5 but ... events/0 is reniced to -5 by default, so it should definitely not be starved. Ingo - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@...r.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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