Bill Davidsen wrote: > Andrea Righi wrote: >> Allow to limit the bandwidth of I/O-intensive processes, like backup >> tools running in background, large files copy, checksums on huge files, >> etc. >> >> This kind of processes can noticeably impact the system responsiveness >> for some time and playing with tasks' priority is not always an >> acceptable solution. >> >> This patch allows to specify a maximum I/O rate in sectors per second >> for each single process via /proc/<PID>/io_throttle (default is zero, >> that specify no limit). >> > It would seem to me that this would be vastly more useful in the real > world if there were a settable default, so that administrators could > avoid having to find and tune individual user processes. And it would > seem far less common that the admin would want to set the limit *up* for > a given process, and it's likely to be one known to the admin, at least > by name. > > Of course if you want to do the effort to make it fully tunable, it > could have a default by UID or GID. Usful on machines shared by students > or managers.
At the moment I'm simply using it to backup my PC by this wrapper: $ cat iothrottle #!/bin/sh [ $# -lt 2 ] && echo "usage: $0 RATE CMD" && exit 1 rate=$1 shift $* & trap "kill -9 $!" SIGINT SIGTERM [ -e /proc/$!/io_throttle ] && echo $rate >/proc/$!/io_throttle wait %1 $ ./iothrottle 100 tar ... But I totally agree with you that setting the limits per-UID/per-GID, instead of per-task, would be actually more useful. Maybe a nice approach would be to define the UID/GID upper bounds via configfs (for example) and allow the users to tune the max I/O rate of their single tasks according to the defined ranges. In this way it could be even possible to define I/O shaping policies, i.e. give a bandwidth of 10MB/s to user A, 20MB/s to user B, 30MB/s to group X, etc. Anyway, I'm wondering if it's possible (and how) to already do this with process containers... -Andrea -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
