On 8/4/2011 10:33 AM, Darac Marjal wrote: > On Thu, Aug 04, 2011 at 10:28:01AM -0500, Stan Hoeppner wrote: >> On 8/4/2011 9:40 AM, lina wrote: >>> On Thu, Aug 4, 2011 at 10:29 PM, Robert Baron >>> <robertbartlettba...@gmail.com> wrote: >>>> have you tried adding an '&' to the tasks you think can be run in >>>> parallel (as in running them in the background (ie 'mycmd myargs &'))? >>> >>> Thanks, >>> >>> "&" is cool. >>> now is fully running, but, there is another thing slow it down, the >>> nice level is 19. why is it so high? are there some root's setting? >> >> Nice levels can be deceiving to those who don't understand how kernel >> scheduling works. For example, it is possible, and happens all the time >> really, that a program with a nice level of 19 will fully consume 100% >> of a processor's time until the program completes. >> >> The only time nice comes into play is when scheduling contention exists. >> This only occurs when there are more ready-to-run processes/threads >> than available processor time slice slots. On an 8 processor desktop >> with the default 1000Hz scheduler you have 8,000 scheduling slices per >> second. So unless your system has 8,001 ready to run processes every >> second, that nice level 19 process will get all the CPU time it needs. >> >> Nice is a relic of early UNIX when businesses and universities would >> have dozens to hundreds of concurrent users on serial TTY terminals >> running programs on a shared single processor machine. Nice allowed >> administrators to provide "fair" access to all users, or to make sure a >> critical batch job got the cycles it needed, even with many users >> running their programs. On today's multi-core desktops, nice is >> literally irrelevant. This is actually the case for most business >> UNIX/Linux systems as well, as almost all of them have excess processor >> capacity for their actual workloads. > > I wouldn't say that nice is completely irrelevant. I run BOINC on my > desktop machine and rely on the BOINC tasks having more nice (if I can > take the opportunity to butcher English) than other tasks such as the > web browser, the window manager and so on. > > Doing so also allows me to tell my CPU scheduler to ignore niced > processes and only spin up the CPU to full speed when an important task > wants it (as opposed to always running at full speed doing the BOINC > calculations).
Thanks for pointing out the exception to the rule. I would think affinity (taskset) is likely more popular with BOINC users than nice, though. I guess you simply don't want an idle core, ever. Must be hard on your electric bill. ;) -- Stan -- To UNSUBSCRIBE, email to debian-user-requ...@lists.debian.org with a subject of "unsubscribe". Trouble? Contact listmas...@lists.debian.org Archive: http://lists.debian.org/4e3ac117.2050...@hardwarefreak.com
