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From: Artyom Tarasenko <atar4qemu@googlemail.com>
Date: Mon, 7 Dec 2009 18:39:28 +0100
Message-ID: <fb8d4f70912070939xd8ef0eera7aa687bc6e004dd@mail.gmail.com>
Subject: Re: [Qemu-devel] irq latency and tcg
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To: Paul Brook <paul@codesourcery.com>
Cc: Blue Swirl <blauwirbel@gmail.com>, qemu-devel@nongnu.org

2009/12/7 Paul Brook <paul@codesourcery.com>:
> On Monday 07 December 2009, Artyom Tarasenko wrote:
>> Can it be that qemu (-system-sparc in my case, but I guess it's more
>> or less similar on all platforms) reacts to irqs slower than a real
>> hardware due to tcg optimizations?
>
> Interrupts generally only trigger at branch instructions, or similar.
>
> Using -icount should give you precise interrupt delivery.

That's what I thought, but as I reported a few days ago, I couldn't
find a good value for icount when using OBP.
I tried a few values but keep getting "qemu: fatal: Raised interrupt
while not in I/O function".
Also I got a report from other person where qemu crashed with another
message: "qemu: fatal: Trap 0x29 while interrupts disabled".

What could be a good value for -icount? Is it host-cpu specific? Isn't
it a bug that qemu crashes [at least] on some icount values?