[Top][All Lists]

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

[Qemu-devel] Re: [PATCH] qemu/pci: optimize pci config handling

From: Paolo Bonzini
Subject: [Qemu-devel] Re: [PATCH] qemu/pci: optimize pci config handling
Date: Thu, 08 Oct 2009 10:23:41 +0200
User-agent: Mozilla/5.0 (X11; U; Linux x86_64; en-US; rv: Gecko/20090922 Fedora/3.0-2.7.b4.fc11 Lightning/1.0pre Thunderbird/3.0b4

What you porpose here is certainly more code than we had.
So why is this a good idea?

Because it avoids the memcpy/memcmp most of the time (when the memcmp
would surely succeed).

Yes :) But at the cost of more code.  I don't think speed
matters there, so less code is good.


  I supposed that would also matter more as the
config space size increases---correct me and dismiss the patch if I am

No, we'll always only look need to look at the header, whatever the size
of the config space.  That's the point of the patch I posted - future
proof against config space size increases, not optimization.

But fewer reads on average will not modify the header, so there will be even fewer memcpy with my patch when the config space will be 4k.


reply via email to

[Prev in Thread] Current Thread [Next in Thread]