| 1 |
Alexander Puchmayr wrote: |
| 2 |
> Am Donnerstag, 6. Dezember 2018, 10:27:31 CET schrieb Dale: |
| 3 |
>> Howdy, |
| 4 |
>> |
| 5 |
>> I mentioned in other threads that I'm doing some upgrades to my system. |
| 6 |
>> My first question is about a CPU upgrade. I currently have this for my |
| 7 |
>> CPU, from cpuinfo: |
| 8 |
>> |
| 9 |
>> AMD Phenom(tm) II X4 955 Processor |
| 10 |
>> |
| 11 |
>> I've bought but not yet installed a FX-8350 CPU. I have this in my |
| 12 |
>> make.conf file: |
| 13 |
>> |
| 14 |
>> CFLAGS="-march=native -O2 -pipe" |
| 15 |
> Compiling the whole system with -march=native might lead to troubles, |
| 16 |
> especially when doing a CPU change. This option means that gcc is determining |
| 17 |
> the type of CPU automatically and adjusts the instruction set used to exactly |
| 18 |
> this CPU. Although, in your case, it is highly likely that your new CPU |
| 19 |
> understands all commands from the old, but I wouldn't bet on it. Its possible |
| 20 |
> that your existing software encounters problems like "illegal instruction" or |
| 21 |
> the like. Very bad if your compiler crashes after CPU replacement, then you |
| 22 |
> cannot emerge anything. I highly recommend using CFLAGS="-O2 -pipe" and |
| 23 |
> nothing more, the performance difference is, if measurable at all, negligible. |
| 24 |
> |
| 25 |
>> USE_CPU="fpu vme de pse tsc msr pae mce cx8 apic sep mtrr pge mca cmov |
| 26 |
>> pat pse36 clflush mmx fxsr sse sse2 ht syscall nx mmxext fxsr_opt |
| 27 |
>> pdpe1gb rdtscp lm 3dnowext 3dnow constant_tsc rep_good nopl nonstop_tsc |
| 28 |
>> extd_apicid pni monitor cx16 popcnt lahf_lm cmp_legacy svm extapic |
| 29 |
>> cr8_legacy abm sse4a misalignsse 3dnowprefetch osvw ibs skinit wdt |
| 30 |
>> nodeid_msr hw_pstate npt lbrv svm_lock nrip_save" |
| 31 |
>> |
| 32 |
> As someone else in this thread already mentioned, USE_CPU is not used. What |
| 33 |
> you're looking for is CPU_FLAGS_X86=..., which defines what cpu-specific options |
| 34 |
> will be enabled for packages supporting it and where it makes sense. See |
| 35 |
> package cpuid2cpuflags for details. |
| 36 |
> |
| 37 |
> Regards |
| 38 |
> Alex |
| 39 |
> |
| 40 |
|
| 41 |
It seems the holiday shopping is slowing down delivery. My fan was |
| 42 |
supposed to be here today but didn't arrive. Since I got time, I'll |
| 43 |
change the CFLAGS for at least the @system stuff, that should get me |
| 44 |
booted for sure. While the native setting makes things easier for |
| 45 |
normal use, I can see the point of not using it when changing CPUs. |
| 46 |
That is one reason for this thread. The CPUs are different and may |
| 47 |
require some changes during the swap. |
| 48 |
|
| 49 |
Is there a easy way to see what if any changes will be made? I did a |
| 50 |
emerge -UDNa @system but it's not showing any change. Does it require a |
| 51 |
emerge -e @system to force the change? Or is it not changing anything? |
| 52 |
|
| 53 |
Thanks much. Better safe than sorry. ;-) |
| 54 |
|
| 55 |
Dale |
| 56 |
|
| 57 |
:-) :-) |
Archives