On 10/05/2011 06:28 AM, Michael S. Tsirkin wrote:
On Mon, Oct 03, 2011 at 10:00:48AM -0500, Anthony Liguori wrote:
Yes, it's easy to quantify. I think the following gives us
the offset before and after, so the difference is the size
we seek, right?
OK, Orit (Cc'd) did some research - this is a booting
while still in grub, size probably does not get much less than that.
windows is said to be much more aggressive in allocating memory.
start offset: 9600673
end offset: 9614933
So we get 15K out of 9M.
So, let's do some napkin math.
Assume that it works out that most of that 15k are 4 byte integers. If we
assume an average name length of 6 characters, a string should be encoded in 8
bytes. That means for every 4 bytes, we add 8 bytes which means we're
increasing by 200%.
That means 45k.
A 1gbit link can xmit at max, 128k in 1ms. So that extra 30k is going to cost
~250us in transmit time if we can get 1gbit. A the default rate limit, it
should cost us right around 1ms.
I guess it's liveable although with 30 network cards, I suspect it gets a heck
of a lot worse.
Regards,
Anthony Liguori
By the way, most of the memory here is pretty much
all uniform I guess, because compressing it gets us:
gzip: 1934169
bzip2 -9: 1462551
So even with aggressive compression, we probably won't be able to get
below 1.5M for memory, two orders of magnitude above device state.
Sounds convincing?
