Date: Thu, 25 Nov 2004 10:09:35 +0100 From: Ronald Klop <ronald-freebsd8@klop.yi.org> To: Rob <spamrefuse@yahoo.com>, freebsd-stable@freebsd.org Subject: port make index (was: Re: make -j$n buildworld : use of -j investigated) Message-ID: <opsh0jp9ge8527sy@smtp.local> In-Reply-To: <41A58766.8030607@yahoo.com> References: <41A2C5C0.3080908@yahoo.com> <2566.10.0.0.26.1101241872.squirrel@10.0.0.26> <41A3EA0F.3080500@yahoo.com> <41A58766.8030607@yahoo.com>
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On Thu, 25 Nov 2004 16:19:02 +0900, Rob <spamrefuse@yahoo.com> wrote: > Rob wrote: >> Brian Szymanski wrote: >> >>> Did you try any machines that used Hyperthreading? I'd be interested to >>> see how those machines fare based on the number of logical and real >>> CPUs. >>> >>> >>>> Although people suggest "-j4" as optimal in general >>>> case, I have come to a very different conclusion: >>>> >>>> 1) single CPU with enough RAM (2 GHz, 512 MB) >>>> there's no significant speed up in the range >>>> "-j1" to "-j9". >>>> So "-j1" is as good as "-j9". >>> >>> >>> >>> If you went to all that trouble, you might as well post the numbers :-) >> Time unit is minutes. >> CPU: 2x800 MHz 2000 MHz 333 MHz >> RAM: 1024 MB 512 MB 64 MB >> -j -------------------------------- >> 1 99 50 276 >> 2 58 49 291 >> 3 58 50 367 >> 4 57 50 547 >> 5 58 49 >> 6 58 50 >> 7 57 50 >> 8 58 50 >> 9 58 50 > > I have run another test on a 700 MHz, 128 MB PC, > and the following equation seems to hold for all > my tests. Calculate: > > time(minutes) * speed(MHz) * nproc / 1000 MHz > > and if this results in approximately 1, the system > is optimized. > > For example, in the above case, > > column 1: > -j1 : 99 * 800 * 2 / 1000 = 1.5 > -j2 : 58 * 800 * 2 / 1000 = 0.928 > > column 2: > -j1 : 50 * 2000 * 1 / 1000 = 1 > > column 3: > -j1 : 276 * 333 * 1 / 1000 = 0.919 > > another PC: > -j1 : 142 * 700 * 1 / 1000 = 0.994 > > -------------- > > All PCs have "standard" hardware. Off-the-shelf > mainboard, IDE harddisks, nothing special really. > > All this is done on 5.3-Stable systems and the time > listed (in minutes) is for the buildworld only: > "make -jn buildworld" > > Rob. Would all this work for 'make index' for the ports also? Or is this more io bound? I can't test this myself, because my laptop is to slow for making these tests any fun. Ronald. -- Ronald Klop, Amsterdam, The Netherlands
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