From: Daniel Walker <dwalker@mvista.com>
To: Russell King <rmk+lkml@arm.linux.org.uk>
Cc: linux-kernel@vger.kernel.org
Subject: Re: Interrupt starvation points
Date: 11 Feb 2005 13:52:19 -0800 [thread overview]
Message-ID: <1108158738.21940.126.camel@dhcp153.mvista.com> (raw)
In-Reply-To: <20050211200424.B28971@flint.arm.linux.org.uk>
On Fri, 2005-02-11 at 12:04, Russell King wrote:
>
> Please substantiate your claim that up() is very expensive on ARM.
> I disagree:
I should have made it clear that I was talking about the RT version of
up() . The RT version doesn't have any assembly in it, and it is
expensive.
> Plus, after you've read the above code, wouldn't you think that adding
> the "enable interrupts + disable interrupts" around an up() operation
> (which itself immediately disables interrupts again) is just adding
> extra instructions to the kernel, which corresponds directly to lower
> performance?
Not in the RT case. However, I never said that was a proper fix, I was
just producing code that helped in my tests.
Daniel
prev parent reply other threads:[~2005-02-11 21:53 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2005-02-11 17:05 Daniel Walker
2005-02-11 17:30 ` Ingo Molnar
2005-02-11 17:36 ` Daniel Walker
2005-02-11 20:04 ` Russell King
2005-02-11 21:52 ` Daniel Walker [this message]
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