[Xen-users] xen4 on debian squeeze, slow mysql in domU

[<s3t@xxxxxxxxxx>]

hi,
i have a mysql server in guest domU on debian squeeze.
when i create test table and do  INSERT INTO test (name, value) VALUES(RAND(), RAND());
Query OK, 1 row affected (0.28 sec)

at other physical server with same configuration
Query OK, 1 row affected (0.00 sec) 

i try this several time but on physical server max value never get over 0.05sec and on VM lowest value was  0.13sec.
another tests:
sysbench
 --num-threads=16 --max-requests=1000 --test=oltp --oltp-table-size=1000
 --mysql-socket=/var/run/mysqld/mysqld.sock --mysql-user=root run     

on physical server:
----------------------------------------------------------------
OLTP test statistics:
    queries performed:
        read:                            15568
        write:                           5228
        other:                           2112
        total:                           22908
    transactions:                        1000   (436.65 per sec.)
    deadlocks:                           112    (48.91 per sec.)
    read/write requests:                 20796  (9080.65 per sec.)
    other operations:                    2112   (922.21 per sec.)

Test execution summary:
    total time:                          2.2901s
    total number of events:              1000
    total time taken by event execution: 35.0599
    per-request statistics:
         min:                                  2.51ms
         avg:                                 35.06ms
         max:                                365.01ms
         approx.  95 percentile:              73.80ms

Threads fairness:
    events (avg/stddev):           62.5000/9.62
    execution time (avg/stddev):   2.1912/0.14
----------------------------------------------------------------


on VM:
----------------------------------------------------------------
OLTP test statistics:
    queries performed:
        read:                            14280
        write:                           5048
        other:                           2020
        total:                           21348
    transactions:                        1000   (177.26 per sec.)
    deadlocks:                           20     (3.55 per sec.)
    read/write requests:                 19328  (3426.02 per sec.)
    other operations:                    2020   (358.06 per sec.)

Test execution summary:
    total time:                          5.6415s
    total number of events:              1000
    total time taken by event execution: 89.6339
    per-request statistics:
         min:                                 35.81ms
         avg:                                 89.63ms
         max:                                275.89ms
         approx.  95 percentile:             115.18ms

Threads fairness:
    events (avg/stddev):           62.5000/1.58
    execution time (avg/stddev):   5.6021/0.03
----------------------------------------------------------------

can someone share his experience with using mysql server in xen domU? 
what can be wrong?


dom0: Xeon E5520 2.27GHz, 8GB ram, debian squeeze, xen-hypervisor-4.0-amd64 Version: 4.0.1-1
domU: vcpus = '8',memory = '4096', debian squeeze
physical server: core2quad Q9300 2.50GHz, 4GB, debian lenny

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