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Re: [Qemu-devel] Anyone seeing huge slowdown launching qemu with Linux 2

From: Avi Kivity
Subject: Re: [Qemu-devel] Anyone seeing huge slowdown launching qemu with Linux 2.6.35?
Date: Tue, 03 Aug 2010 20:08:26 +0300
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 On 08/03/2010 07:56 PM, Richard W.M. Jones wrote:
On Tue, Aug 03, 2010 at 07:44:49PM +0300, Avi Kivity wrote:
  On 08/03/2010 07:28 PM, Richard W.M. Jones wrote:
I have posted a small patch which makes this 650x faster without
appreciable complication.
It doesn't appear to support live migration, or hiding the feature
for -M older.
AFAICT live migration should still work (even assuming someone live
migrates a domain during early boot, which seems pretty unlikely ...)

Live migration is sometimes performed automatically by management tools, which have no idea (nor do they care) what the guest is doing.

Maybe you mean live migration of the dma_* global variables?  I can
fix that.


It's not a good path to follow.  Tomorrow we'll need to load 300MB
initrds and we'll have to rework this yet again.
Not a very good straw man ...  The patch would take ~300ms instead
of ~115ms, versus something like 2 mins 40 seconds with the current

It's still 300ms extra time, with a 900MB footprint.

btw, a DMA interface which blocks the guest and/or qemu for 115ms is not something we want to introduce to qemu. dma is hard, doing something simple means it won't work very well.

error compiling committee.c: too many arguments to function

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