J. Roeleveld wrote: > On December 8, 2018 6:23:04 PM UTC, Dale <rdalek1...@gmail.com> wrote: > > Alexander Puchmayr wrote: > > Am Donnerstag, 6. Dezember 2018, 10:27:31 CET schrieb Dale: > > Howdy, I mentioned in other threads that I'm doing some > upgrades to my system. My first question is about a CPU > upgrade. I currently have this for my CPU, from cpuinfo: > AMD Phenom(tm) II X4 955 Processor I've bought but not yet > installed a FX-8350 CPU. I have this in my make.conf file: > CFLAGS="-march=native -O2 -pipe" > > Compiling the whole system with -march=native might lead to > troubles, especially when doing a CPU change. This option > means that gcc is determining the type of CPU automatically > and adjusts the instruction set used to exactly this CPU. > Although, in your case, it is highly likely that your new CPU > understands all commands from the old, but I wouldn't bet on > it. Its possible that your existing software encounters > problems like "illegal instruction" or the like. Very bad if > your compiler crashes after CPU replacement, then you cannot > emerge anything. I highly recommend using CFLAGS="-O2 -pipe" > and nothing more, the performance difference is, if measurable > at all, negligible. > > USE_CPU="fpu vme de pse tsc msr pae mce cx8 apic sep mtrr > pge mca cmov pat pse36 clflush mmx fxsr sse sse2 ht > syscall nx mmxext fxsr_opt pdpe1gb rdtscp lm 3dnowext > 3dnow constant_tsc rep_good nopl nonstop_tsc extd_apicid > pni monitor cx16 popcnt lahf_lm cmp_legacy svm extapic > cr8_legacy abm sse4a misalignsse 3dnowprefetch osvw ibs > skinit wdt nodeid_msr hw_pstate npt lbrv svm_lock nrip_save" > > As someone else in this thread already mentioned, USE_CPU is > not used. What you're looking for is CPU_FLAGS_X86=..., which > defines what cpu-specific options will be enabled for packages > supporting it and where it makes sense. See package > cpuid2cpuflags for details. Regards Alex > > > It seems the holiday shopping is slowing down delivery. My fan was > supposed to be here today but didn't arrive. Since I got time, I'll > change the CFLAGS for at least the @system stuff, that should get me > booted for sure. While the native setting makes things easier for > normal use, I can see the point of not using it when changing CPUs. > That is one reason for this thread. The CPUs are different and may > require some changes during the swap. > > Is there a easy way to see what if any changes will be made? I did a > emerge -UDNa @system but it's not showing any change. Does it require a > emerge -e @system to force the change? Or is it not changing anything? > > Thanks much. Better safe than sorry. ;-) > > Dale > > :-) :-) > > > A CFLAGS change requires a rebuild of all packages done with gcc. I am > not aware of a simple way of only doing those, so a "emerge --empty > @world" will be needed. > > -- > Joost > -- > Sent from my Android device with K-9 Mail. Please excuse my brevity.
Based on the output, that's what I was thinking. Emerge picks up on other USE changes but it seems it only grabs the CFLAGS during the compile/configure phase for each package. Would this change the kernel image as well or would it remain the same? I may build a new kernel just to be sure. One good thing about this, I can compare the times with current CPU and new CPU later and get a rough idea of speed increases. ;-) Pardon me while I generate some heat. o_O Dale :-) :-)
