Date: Thu, 15 Mar 2012 14:21:13 -0600 From: Ian Lepore <freebsd@damnhippie.dyndns.org> To: "O. Hartmann" <ohartman@mail.zedat.fu-berlin.de> Cc: Current FreeBSD <freebsd-current@freebsd.org> Subject: Re: CURRENT: make -jX buildworld doesn't work Message-ID: <1331842873.8403.4.camel@revolution.hippie.lan> In-Reply-To: <4F60D079.80406@mail.zedat.fu-berlin.de> References: <4F60A167.7020609@mail.zedat.fu-berlin.de> <1331737736.1099.30.camel@revolution.hippie.lan> <4F60D079.80406@mail.zedat.fu-berlin.de>
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On Wed, 2012-03-14 at 18:08 +0100, O. Hartmann wrote: > On 03/14/12 16:08, Ian Lepore wrote: > > On Wed, 2012-03-14 at 14:47 +0100, O. Hartmann wrote: > >> This is no compalin, since make buildworld works with one thread. > >> > >> But I'd like to report a funny thing I witnessed. > >> > >> On two boxes equipted with Core2Dou CPUS (E8500, 2 cores/threads, > >> Q6600, 4 cores/threads) a parallel make buildworld works fine with the > >> most recent sources of FreeBSD 10.0-CURRENT/amd64 (both boxes have 8 GB > >> RAM, both boxes use a very close/similar setup and configuration). > >> > >> I moved in my lab towards a brand new Sandy-Bridge-E box with 32GB RAM > >> and the CPU is a Core i7-3930X with six cores/12 threads. On this box, > >> even "make buildworld" with -j2 fails to build. It builds fine with a > >> vanilla "make buildworld". > >> > >> Also funny is, that even with only one thread, the 3 GHz Core2Duo > >> methusalem systems "outperform" in compile time the 3,2 GHZ driven Intel > >> youngster. > >> > >> Maybe there is an issue in FreeBSD 10 with the TURBO BOOST? I'm a bit > >> time constraint now, but I'm willing to do some tests with advices from > >> the experts. > >> > >> Lets give you some informations I think it could be valuable. Please > >> request more, if this isn't sufficient. > >> > >> I realize/I'm aware that both hardware and OS are brandnew! But > >> hopefully this is something important and could be "fixed" - if my > >> observation is a real observation ... > >> > >> Regards, > >> Oliver > > [SNIP] > > > > > There was a change (r232793) a few days ago to make turbo boost work, > > more info in this thread: > > > > http://lists.freebsd.org/pipermail/freebsd-current/2012-March/032434.html > > > > I wasn't able to get it to work just by tweaking the rc.conf knobs, but > > I suspect the reason may be because I have non-standard devd.conf. I > > worked around it and haven't had time to look for the cause yet. > > > > In trying to explain the compile time differences between two systems, > > one of the first things I'd look at would be differences in the disks. > > In my experience, IO performance has as big an influence on build time > > as processor speed and number of cores. > > > > I just updated my -current sources and did a fresh buildworld and > > buildkernel using both -j2 and -j12 and had no problems on a 6-core > > Xeon. I know "make xdev" fails with -jN but I haven't seen failures on > > any other targets. There was a checkin recently that added some .ORDER > > stuff for -jN but it only affected building usr.sbin/acpi. > > > > -- Ian > > The change has already been used. But no change. > > The disks are on all systems the same, but the new box has SATA 6GB and > the WD 640GB "Caviar black" disk claims also be SATA 6GB. > You're right, disk I/O has a great impact. And I realized that FreeBSD > 9/10 have a big problem with the Patsburg-based X79 chipset, as far as I > can see - or it is simply a coincidence. Since the disks are attached to > the X79 chipset's SATA 6GB port, I have sometimes strange elongated > access times. When doing a simple diskper measurement, the raw > performance of the disk reveals itself as slightly better than with SATA > 3GB. > > By the way, my last buildworl took 1 hour. The buildworld before 3 > hours. Same load, same box, same OS revision. funny. > > I stay tuned. At the time, it doesn't bother me much. I thought it is > just worth to be mentioned ... > > Regards, > > Oliver > Just to give you a point of comparison... My build machine is a 6-core Xeon W3680 running at 4.25GHz (yes, that's overclocked from stock 3.3), hyperthreading disabled, 12G ram, and all builds are done using filesystems on SSD drives connected to a SATA-2 controller. Using /dev/null for src.conf and make.conf so that it's a completely stock build, I get these build times for a "make buildworld buildkernel" -j1 63 minutes -j2 35 minutes -j6 19 minutes -j12 18 minutes I wonder if your 1hr/3hr difference is due to caching? If so, that would seem to point to big trouble with disk performance. I re-did the -j6 build after unmounting/remounting the filesystem to clear the cache and the difference was less than 30 seconds, but that's with SSD drives. Hmmm, I just realized I'm using MODULES_OVERRIDE="agp drm" so it's not quite a completely-stock/GENERIC build. -- Ian
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