atop is a daemon sampling some metrics on a server such as processlist, memory, cpu usage...
atop let us browse the per 10 minutes (configurable) samples with t and T and even filter out the process list with P (then enter: php).
atop -r /var/log/atop.log.1
Get samples from previous log file between 01:59 and 02:00
atop -r /var/log/atop.log.1 -b 01:59 -e 02:00
Press m for memory report:
PID VSTEXT VSIZE RSIZE VGROW RGROW MEM CMD 10815 7442K 7.1G 2.6G 161.1M 179.4M 68% php
Press d for disk report:
PID RDDSK WRDSK WRDSK_CANCEL DSK CMD 10815 69824K 4.0G 4.0G 99% php
RDDSK : number of reads, WRDSK : number of writes.
atop 1.27 will give us the full commandline though it is not in Ubuntu Precise.