From: David Howells <dhowells@redhat.com>
To: Ingo Molnar <mingo@elte.hu>
Cc: David Howells <dhowells@redhat.com>,
john stultz <johnstul@us.ibm.com>, Adrian Bunk <bunk@stusta.de>,
Andrew Morton <akpm@osdl.org>,
Arjan van de Ven <arjan@linux.intel.com>,
linux-kernel@vger.kernel.org, Jeff Garzik <jeff@garzik.org>,
netdev@vger.kernel.org
Subject: Re: [PATCH] FRV: do_gettimeofday() should no longer use tickadj
Date: Wed, 06 Sep 2006 13:30:56 +0100 [thread overview]
Message-ID: <13982.1157545856@warthog.cambridge.redhat.com> (raw)
In-Reply-To: <20060906094301.GA8694@elte.hu>
Ingo Molnar <mingo@elte.hu> wrote:
> btw., would be nice to convert it to genirq (and irqchips) too =B-) That
> would solve the kind of disable_irq_lockdep() breakage that was reported
> recently.
I can think of reasons for not using that stuff also.
(1) Passing "struct pt_regs *regs" around is a complete waste of resources on
FRV. It's in GR28 at all times and can thus be accessed directly.
(2) All the little operations functions cause unnecessary jumping, jumps that
icache lookahead can't predict because they're register-indirect.
(3) ACK'ing and controlling interrupts has to be done by groups.
(4) No account is taken of interrupt priority.
(5) The FRV CPU doesn't tell me which IRQ source fired. Much of the code
I've got is stuff to try and work it out. I could just blindly poll all
the sources attached to a particular interrupt level, but that seems
somehow less efficient.
David
BTW, have you looked at my patch to fix lockdep yet?
next prev parent reply other threads:[~2006-09-06 12:33 UTC|newest]
Thread overview: 25+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <20060901015818.42767813.akpm@osdl.org>
2006-09-05 13:25 ` 2.6.18-rc5-mm1: {dis,en}able_irq_lockdep_irqrestore compile error Adrian Bunk
2006-09-05 15:21 ` [PATCH] FRV: Fix " David Howells
2006-09-06 12:50 ` Ingo Molnar
2006-09-05 15:27 ` [PATCH] NOMMU: Move the fallback arch_vma_name() to a sensible place David Howells
2006-09-05 15:29 ` [PATCH] NOMMU: Provide page_mkclean() for NOMMU David Howells
2006-09-05 15:31 ` [PATCH] NOMMU: Make lib/ioremap.c conditional David Howells
2006-09-05 15:35 ` [PATCH] FRV: do_gettimeofday() should no longer use tickadj David Howells
2006-09-06 1:46 ` john stultz
2006-09-06 9:27 ` David Howells
2006-09-06 9:43 ` Ingo Molnar
2006-09-06 12:30 ` David Howells [this message]
2006-09-06 12:56 ` Ingo Molnar
2006-09-06 14:46 ` David Howells
2006-09-06 23:01 ` Benjamin Herrenschmidt
2006-09-07 9:55 ` David Howells
2006-09-07 10:26 ` Ingo Molnar
2006-09-07 13:34 ` David Howells
2006-09-07 22:53 ` Benjamin Herrenschmidt
2006-09-08 10:25 ` David Howells
2006-09-08 11:05 ` Benjamin Herrenschmidt
2006-09-08 12:24 ` David Howells
2006-09-08 12:29 ` David Howells
2006-09-11 4:06 ` Benjamin Herrenschmidt
2006-09-09 5:46 ` Ingo Molnar
2006-09-11 10:46 ` David Howells
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