RE: [Xen-devel] More network tests with xenoprofile this time

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

> I had a chance to run a couple of the netperf tests with 
> xenoprofile.  I am still having some trouble with 
> multi-domain profiles (probably user error), but I have been 
> able to profile dom0 while running 2 types of tests.  I was 
> surprised to see as much as 50% cpu in hypervisor on these tests:
> 
> netperf tcp_stream 16k msg size, dom1 -> dom2 dom0 is on 
> cpu0, HT thread 0, dom1 is on cpu1, HT thread 0,
> dom2 is on cpu1, HT thread 1.

Let's ignore the domU <-> domU results for the moment as we know about
the problem with lack of batching in this scenario. Let's dig into the
dom1 -> external.

First off, are these figures just for CPU 0 HT 0? i.e. just dom0 so we
don't see where time goes in the domU? How is idle time on the CPU
reported?

Spending 18% of the time handling interrupts in Xen is surprisingy (at
least to me). 

What interrupt rate are you observing? What are the default tg3
interrupt coallescing settings? What interrupt rate do you get on
native? Also, what hypercall rate are you seeing?  

(It would be good to put this in context of the rx/tx packet rates).

Is the Ethernet NIC sharing an interrupt with the USB controller per
chance?

Seeing find_domain_by_id and copy_from_user so high up the list is
pretty surprising. 

Cheers,
Ian

> netperf tcp_stream 16k msg size, dom1 -> external host dom0 
> is on cpu0, HT thread 0, dom1 is on cpu1, HT thread 1.
> 
> 
> Throughput is ~940 Mbps, wire speed.
> 
> xenoprofile opreport:
> 
>   4244562 49.9375 xen-unstable-syms
>   4110594 48.3614 vmlinux-2.6.11-xen0-up
>    132643  1.5606 oprofiled
>      4212  0.0496 libc-2.3.3.so
>      2892  0.0340 libpython2.3.so.1.0
> 
> xenoprofile opreport -l:
> 
>     828587   9.75      xen-unstable-syms end_level_ioapic_irq
>     712035   8.38      xen-unstable-syms mask_and_ack_level_ioapic_irq
>     370265   4.36 vmlinux-2.6.11-xen0-up      net_tx_action
>     323797   3.81 vmlinux-2.6.11-xen0-up           ohci_irq
>     282005   3.32 vmlinux-2.6.11-xen0-up      tg3_interrupt
>     273161   3.21      xen-unstable-syms  find_domain_by_id
>     234726   2.76      xen-unstable-syms          hypercall
>     206693   2.43      xen-unstable-syms do_update_va_mapping
>     203758   2.40      xen-unstable-syms __copy_from_user_ll
>     201665   2.37      xen-unstable-syms       do_mmuext_op
>     195020   2.29 vmlinux-2.6.11-xen0-up         nf_iterate
>     184295   2.17 vmlinux-2.6.11-xen0-up       nf_hook_slow
>     172110   2.02 vmlinux-2.6.11-xen0-up             tg3_rx
>     164337   1.93 vmlinux-2.6.11-xen0-up      net_rx_action
>     141999   1.67      xen-unstable-syms      do_mmu_update
>     139120   1.64 vmlinux-2.6.11-xen0-up         fdb_insert
>     122483   1.44      xen-unstable-syms       mod_l1_entry
>     122017   1.44      xen-unstable-syms  put_page_from_l1e
>     111159   1.31      xen-unstable-syms  get_page_from_l1e
>     109921   1.29      xen-unstable-syms             do_IRQ
>      99847   1.17 vmlinux-2.6.11-xen0-up    br_handle_frame
>      99709   1.17      xen-unstable-syms      get_page_type
>      93613   1.10 vmlinux-2.6.11-xen0-up              kfree
>      90885   1.07 vmlinux-2.6.11-xen0-up           end_pirq
> 
> 
> -Andrew
> 
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