Postal 56% waits for flock_lock_file_wait

[Ananiev, Leonid I]

A benchmark
             'postal -p 16 localhost list_of_1000_users'
56% of run time waits for flock_lock_file_wait;
Vmstat reports that 66% cpu is idle and  vmstat bi+bo=3600 (far from
max).
Postfix server with FD_SETSIZE=2048 was used.
Similar results got for sendmail. 
Wchan is counted by
            while :; do
                        ps -o user,wchan=WIDE-WCHAN-COLUMN,comm;
sleep 1;
           done | awk '/ postfix /{a[$2]++}END{for (i in a) print
a[i]"\t"i}'
If ext2 fs is used the Postal throughput is twice more and bi+bo by 50%
less while  flock_lock_file_wait 60% still.

Is flock_lock_file_wait considered as a performance limiting waiting for
similar applications in smp?

Leonid
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