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
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