Compiler flags and memory usage

[drago01]

On Mon, Jun 16, 2014 at 8:02 PM, Antonio Trande <anto.trande at gmail.com> wrote:
> On 06/16/2014 12:12 AM, Kevin Kofler wrote:
>> Antonio Trande wrote:
>>> To pass these problems, I had to decrease '-O' optimization flag
>>> gradually to '-O1' or '-O0', latest attempt is the removal of '-pipe'
>>> from RPM_OPT_FLAGS.
>>>
>>> What's best choice in these cases?
>>
>> Definitely not -O0, that generates really crappy (slow and large) code. I'd
>> also not recommend -O1. If you must change something, remove -pipe, that
>> only makes builds slower (given sufficient RAM for the piping), but does not
>> affect the quality of the generated code.
>
> On 06/16/2014 12:37 AM, Reindl Harald wrote:
>> Am 16.06.2014 00:12, schrieb Kevin Kofler:
>>
>> i would add here
>> %_smp_mflags -j1
>>
>> if it comes to reduce memory due compile
>>
>
> Thanks for your tips.
>
> On 06/16/2014 03:54 AM, John Reiser wrote:>> coin-or-lemon is still in
> f20 updates-testing repos
>>
>> Please mention such facts early and prominently.  It saves time
>> for those who try to help you.
>
> Okay.
>
>>
>>> So my RAM is not adequate.
>>
>> It *can* work, but your machine is not configured properly for large
> compiles:
>> -----
>>> $ cat /proc/swaps
>>> Filename                             Type            Size    Used    Priority
>>> $     ### /proc/swaps is empty.  There is no swap space.
>> -----
>
> Honestly, I already had a swap partition but I never verified if it was
> available and used.
>
>> Get some swap space, either a disk partition, or a file of at least 6GB:
>>     dd if=/dev/zero of=my_swap_space bs=32k count=200k
>>     mkswap my_swap_space
>>     swapon my_swap_space
>>
>
> Okay, I have made ready a swap partition mounted at boot time by
> changing /etc/fstab; 10GB should be sufficient. This is the swap after a
> first *complete* compilation of SeqAn (at last):
>
> $ cat /proc/swaps
> Filename     Type               Size    Used    Priority
> /dev/sda2    partition         10485756 188752  -1
>
> My hardware needs more than 1 hour just for pair_align.cpp with "make
> -j1" in .spec. In any case, now I can complete SeqAn building on my PC.
>
> Thank you very much.

Given today's memory prices ... just buy an additional ram stick and
be done with it ;)