virtualbox.org

Hello,

Host: VB 4.3.10 on CentOS 6.5 (2.6.32)
Guest: Ubuntu 13.10 (3.11.0)
Everything runs well except memcached (so far).. When running the guest with 2 or more CPUs:

mdv1:~$ memcslap --server 127.0.0.1:11211
Threads connecting to servers 1
Took 2.997 seconds to load data

When running the guest with 1 CPU:

mdv1:~$ memcslap --server 127.0.0.1:11211
Threads connecting to servers 1
Took 0.302 seconds to load data

I've tried with memcached 1.4.10 and 1.4.17, same results. I've also tried the same guest under the same scenarios except on a OSX/10.7.5 host, same results. strace on memcached reveals that they're essentially doing the same thing in both scenarios (epoll, etc). Tried running memcached in 1 thread, 4 threads, 16 threads, same result. Tried before and after installing vbox guest additions, same.

Guest settings: 4096MB, PAE/NX off, VT-x/AMD-V on, Nested Paging on, Host I/O Cache on SATA drive on.

I'm getting this from dmesg:
mdv1:~$ dmesg|grep CPU
[ 0.000000] CPU MTRRs all blank - virtualized system.
[ 0.000000] ACPI: SSDT 00000000dfff02b0 001CC (v01 VBOX VBOXCPUT 00000002 INTL 20100528)
[ 0.000000] smpboot: Allowing 4 CPUs, 0 hotplug CPUs
[ 0.000000] setup_percpu: NR_CPUS:256 nr_cpumask_bits:256 nr_cpu_ids:4 nr_node_ids:1
[ 0.000000] PERCPU: Embedded 29 pages/cpu @ffff88011fc00000 s86720 r8192 d23872 u524288
[ 0.000000] SLUB: HWalign=64, Order=0-3, MinObjects=0, CPUs=4, Nodes=1
[ 0.000000] RCU restricting CPUs from NR_CPUS=256 to nr_cpu_ids=4.
[ 0.000000] Offload RCU callbacks from all CPUs
[ 0.000000] Offload RCU callbacks from CPUs: 0-255.
[ 0.019442] CPU: Physical Processor ID: 0
[ 0.020018] CPU: Processor Core ID: 0
[ 0.020026] mce: CPU supports 0 MCE banks
[ 0.091463] smpboot: CPU0: Intel(R) Xeon(R) CPU X3450 @ 2.67GHz (fam: 06, model: 1e, stepping: 05)
[ 0.092000] Performance Events: unsupported p6 CPU model 30 no PMU driver, software events only.
[ 0.092000] mce: CPU supports 0 MCE banks
[ 0.103667] TSC synchronization [CPU#0 -> CPU#1]:
[ 0.103674] Measured 89831 cycles TSC warp between CPUs, turning off TSC clock.
[ 0.103795] mce: CPU supports 0 MCE banks
[ 0.115706] mce: CPU supports 0 MCE banks
[ 0.127526] Brought up 4 CPUs
[ 0.675795] ledtrig-cpu: registered to indicate activity on CPUs
[ 2.261072] microcode: CPU0 sig=0x106e5, pf=0x4, revision=0x616
[ 2.349037] microcode: CPU1 sig=0x106e5, pf=0x4, revision=0x616
[ 2.372894] microcode: CPU2 sig=0x106e5, pf=0x4, revision=0x616
[ 2.390995] microcode: CPU3 sig=0x106e5, pf=0x4, revision=0x616

Any ideas?

Thanks

I don't have any ideas but I stopped using guests with more than 1 CPU on Mac OSX hosts over a year ago. There was either no difference in speed or the guest actually ran slower. One probably shouldn't run more than half the available cores than the host has.

Minimum information needed for assistance.