The following are examples of php_flowtime.d. This is a simple script to trace the flow of PHP functions. Here it traces the example program, Code/Php/func_abc.php # php_flowtime.d C TIME(us) FILE DELTA(us) -- FUNC 0 3646108339057 func_abc.php 9 -> func_a 0 3646108339090 func_abc.php 32 -> sleep 0 3646109341043 func_abc.php 1001953 <- sleep 0 3646109341074 func_abc.php 31 -> func_b 0 3646109341098 func_abc.php 23 -> sleep 0 3646110350712 func_abc.php 1009614 <- sleep 0 3646110350745 func_abc.php 32 -> func_c 0 3646110350768 func_abc.php 23 -> sleep 0 3646111362323 func_abc.php 1011554 <- sleep 0 3646111362351 func_abc.php 27 <- func_c 0 3646111362361 func_abc.php 10 <- func_b 0 3646111362370 func_abc.php 9 <- func_a ^C The fifth column is indented by 2 spaces to show when a new function begins. This shows which function is calling which - the output above begins by showing that func_a() began; slept, and returned from sleep; and then called func_b(). The TIME(us) column shows time since boot. The DELTA(us) column shows time from that line to the previous line, and so can be a bit tricky to read. For example, the second line of data output (skipping the header) reads as "the time from func_a() beginning to calling the sleep function beginning was 32 microseconds". The FILE column shows file that was being executed. If the output looks shuffled, check the CPU "C" and "TIME" columns, and post sort based on TIME if necessary. See Notes/ALLflow_notes.txt for important notes about reading flow outputs.