On Sun, 27 Sep 2015 15:19:41 -0500 Bruce Dubbs <bruce.du...@gmail.com> wrote:
> so the patch doesn't make any difference for timing, at least with my > i7-5820K CPU. Bruce, Thanks for letting us know. Given the comments in that make bug thread, I'm pretty sure there *was* a problem here with regard to the performance of fork() versus vfork(). I guess they fixed that in more recent kernels. ... Yep, from late 2010: http://stackoverflow.com/questions/4259629/what-is-the-difference-between-fork-and-vfork "With most current kernels, however, including Linux, the primary benefit of vfork has disappeared because of the way fork is implemented. Rather than copying the whole image when fork is executed, copy-on-write techniques are used." Maybe the folks with make performance problems were the ones running older kernels. On Mon, 28 Sep 2015 00:27:24 +0100 Ken Moffat <zarniwh...@ntlworld.com> wrote: > For the kernel, if I stop and repeat sometimes it builds ok and > soemtimes it doesn't. I think that is the definition of "flakey > hardware". Ken, In that case, I bet it is either a thermal or a power supply problem - the -j4 pulls more power and makes more CPU heat. If there isn't any/enough thermal grease on the CPU, the heat sink is not mounted correctly, the CPU core voltage is not correct (or clock speed too high), or the CPU fan isn't moving enough air over the right parts (and also through the case), problems like this can happen under high load. Ditto for a power supply or power connectors that cannot handle the demanded current. Check that heat sink, check the core voltage and setting. Also, where the power connector goes into the motherboard - look for heat discoloration or other signs of burning. Well, I'm glad to know there doesn't seem to be an overall problem with AMD and Linux or else, as much as I do like AMD, I would have to avoid buying an AMD-based system. Cheers, Mike -- http://lists.linuxfromscratch.org/listinfo/blfs-support FAQ: http://www.linuxfromscratch.org/blfs/faq.html Unsubscribe: See the above information page
