These straces show process takes ~0 sec to complete. Not backing up what you experienced.
If this server is serving traffic, it may be difficult to pick a right lsphp5 process for the testing since many lsphp5 processing running. If that's the case, I would suggest you switch to Apache during the test period and have LSWS run in parallel on a different port (say 2080 when set Apache offset port to 2000). then you can strace lsphp5 process for testing (if it is still slow).
strace -ttT -p pid