[sheepdog-users] 50.000 iops per VM
s.priebe at profihost.ag
Mon Jul 9 20:13:10 CEST 2012
thanks for your reply.
Am 09.07.2012 16:49, schrieb Christoph Hellwig:
> Before I would like to let you try 29bfdbd6a95fdf8d827e177046dbab12ee342611
> or earlier?
I already tried that. It gives me the same results.
>>> Can you also do a perf record -g on both a storage node and the
>>> kvm box to see if there's anything interesting on them?
>> Option -g is not known by my perf command?
> perf record -g records the callgraph, and it's been there for a long
> time. Did you try that above line or something like perf -g record?
*argh* i really tried -g record ;-( i'm on holiday right now so it will
take some days. What is the expected output of this command? Should i
>> is a perf record sleep 10 enough? Should i upload then the data file
> Would be nice to get a slightly long run.
>> Snapshot of perf top from KVM host:
>> 14.96% [kernel] [k] _raw_spin_lock
> With the callchains we could expand what spinlock we hammer here.
>> 8.13% kvm [.] 0x00000000001d8084
> Also if kvm/qemu is self-build can you build it with -g to get debug
> info? If not see if there is a qemu-dbg/kvm-dbg or similar package for
> your distribution.
It is self build - i'll do a debug.
>> Snapshot of perf top from sheep node (not acting as the gateway /
>> target for kvm):
>> 2,78% libgcc_s.so.1 [.] 0x000000000000e72b
>> 2,21% [kernel] [k] __schedule
>> 2,14% [kernel] [k] ahci_port_intr
>> 2,08% [kernel] [k] _raw_spin_lock
>> 1,77% [kernel] [k] _raw_spin_lock_irqsave
>> 1,15% [kernel] [k] ahci_interrupt
>> 1,11% [kernel] [k] ahci_scr_read
>> 0,94% [kernel] [k] kmem_cache_alloc
>> 0,90% [kernel] [k] _raw_spin_lock_irq
>> 0,81% [kernel] [k] menu_select
>> 0,76% [kernel] [k] _raw_spin_unlock_irqrestore
>> 0,73% libpthread-2.11.3.so [.] pthread_mutex_lock
>> 0,70% libc-2.11.3.so [.] vfprintf
> Mostly not spending any noticable CPU time, which is quite interesting.
Yes the sheep acting as gateway is taking 20x times more CPU than the
node sheep processess.
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