RE: [Xen-devel] x86-64 Net Performance

["Ian Pratt" <m+Ian.Pratt@xxxxxxxxxxxx>]

> Update: I went ahead and compiled glibc without TLS / NPTL.  

For 64 bit Xen you don't need to worry about TLS/NPTL.

> Also, I realized that I wasn't allocating all my physical 
> memory to Domain0 for these tests, so I was giving Xen a 
> disadvantage.  It didn't change much, but those tests have 
> been re-done.
> 
> Here's the odd thing: disabling TLS for 64-bit improved 
> native performance by around 10%, but had no effect on Xen.

How did you disable TLS on 64 bit? It's odd that it would have any
effect on native or xen, let alone such a dramatic one. Are you sure
about this test?

>                 Native  Domain0 Penalty
> 64-bit TLS      50.2    65.0    29.5%
> 64-bit no TLS   44.8    65.0    45.1%
> 32-bit TLS      59.6    59.5    -0.2%
> 32-bit no TLS   59.6    60.2     1.0%

It looks like we need to investigate x86_64 networking performance. We
may well not be getting the pipelining that we do in 32bit, though I
can't immediately think why,

Ian 

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