Hi all, I appear to be using huge amounts of CPU time, and I am trying to work out why. The commands I ran and their output are in systime_log at http://urchin.earth.li/~ian/systime/, and all the source and other output is there too. Essentially the program uses more system time than user time according to time (bash built-in, Linux x86), and I'd like to know why (or more precisely I'd like to reduce it, but knowing why seems like a good first move :-) ). I'm somewhat confused as to why the numbers given by time and strace -c don't match, but nevertheless it looks to me like the time must be due to one or more of: rt_sigprocmask(SIG_SETMASK, [], NULL, 8) = 0 rt_sigprocmask(SIG_BLOCK, [], [], 8) = 0 --- SIGVTALRM (Virtual timer expired) --- sigreturn() = ? (mask now []) I'm not sure where to go from here. Any suggestions? Thanks Ian