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And it is more. Flag optimization can give you a speed boost. But this boost will be very marginal with most software, and for the other, the software developers of the program, or the package maintainers of the distribution, will do the profiling for you. | And it is more. Flag optimization can give you a speed boost. But this boost will be very marginal with most software, and for the other, the software developers of the program, or the package maintainers of the distribution, will do the profiling for you. | ||
− | It is much more, but I skip it... In short, the same unsafe cflag can behave differently with different gcc versions and different source codes... ... ... -:) | + | It is much more, but I skip it... In short, the same unsafe cflag can behave differently with different gcc versions and different source codes... ... ... In consequence: don't trust the optimization made by software developers, they just don't have the same system than yours. -:) It is also for that than it is best to set sane cflags into /etc/make.conf |
And last, it is a much better way to get a speed boost: compile your kernel with a processor type that is corresponding to the processor in your box. On gentoo, you already know that. With the other distributions, you have to install the kernel sources that correspond to your kernel in use, copy the .config file of this kernel into the kernel sources, run "make oldconfig" and "make menuconfig". In this menu, go to "Processor tape and features" -> "Processor family" and select the most appropriated family. Exit the menu, compile and install the kernel and its modules. For more information of the process of kernel compilation and installation, take a look at the forum of your distribution. It can be important distribution specific tricks that will make this easier and safer (in case of system upgrade and so on). | And last, it is a much better way to get a speed boost: compile your kernel with a processor type that is corresponding to the processor in your box. On gentoo, you already know that. With the other distributions, you have to install the kernel sources that correspond to your kernel in use, copy the .config file of this kernel into the kernel sources, run "make oldconfig" and "make menuconfig". In this menu, go to "Processor tape and features" -> "Processor family" and select the most appropriated family. Exit the menu, compile and install the kernel and its modules. For more information of the process of kernel compilation and installation, take a look at the forum of your distribution. It can be important distribution specific tricks that will make this easier and safer (in case of system upgrade and so on). |
Revision as of 19:24, 21 October 2011
Hi all,
Me and linux
I have a technical background in electronic, all the electronic from the vacuum tubes to DSP processors. I prefer the analog electronic and I buy my first PC, a x86, when I see what could be archived with an analog electronic simulation software.
I learned English with books on electronics, so, it is not terrific -:)
I am an old linux user, my first working linux installation was a real pain, one week of work to get it running on my x386 box. A few weeks later, I try on my Amiga 2000, and surprise, in one hour the same work was done. But the 1.3 Amiga OS was so better, than i just installed it back... Now, the heart of my box is a phenom, and it just work like hell with gentoo-linux. This is the fastest and more stable box I never had. The stability of this AMD box is truly amazing, and its speed is amazing too.
For the distributions, Suse, Suse again, Suse always. But I get sick of a few things like its inability to deal reliably on the long run with multiple repositories. I shifted to gentoo. I learned a lot more on linux but eventually not enough, and I get back to Suse after an unrepairable system crash. Same problem than before with it, so I shifted to debian. Debian is not better with its management of multiple repositories, so I shifted back to gentoo. This time, I took my time to experiment with the most critical part of the gentoo install: the cflags.
My conclusion is that, if you use sane cflags, a gentoo system is more stable than even debian. But with insane cflags, it is possible to crash it to death in a few months, days, or even hours, and the only way to get it back will be trough, like with window$, a format and a full reinstall.
What are sane cflags: the ones used in the gentoo handbook. What are insane cflags: any other combination.
Conclusion bis: if you are not 100% sure, use the same cflags than in the handbook.
The problem posed by the cflags is multiple. They are optimization flags used by gcc when compiling a program. On one hand, you can get a speed boost with them. On the other hand, more optimizations can introduce very strange bugs that can be very difficult to trace: as example, a software can compile just fine, but you can get troubles during its execution, and that even if it doesn't crash.
It is 2 solutions to that problem: 1) Use sane cflags as explained before. (easy, read and paste -:) 2) Do flags optimization for each single program in the box with a profiler like valgrind.
The problem with 2) is than I know nobody that have the time to do that with each and every single installed package, and to redone this work at each upgrade.
And it is more. Flag optimization can give you a speed boost. But this boost will be very marginal with most software, and for the other, the software developers of the program, or the package maintainers of the distribution, will do the profiling for you.
It is much more, but I skip it... In short, the same unsafe cflag can behave differently with different gcc versions and different source codes... ... ... In consequence: don't trust the optimization made by software developers, they just don't have the same system than yours. -:) It is also for that than it is best to set sane cflags into /etc/make.conf
And last, it is a much better way to get a speed boost: compile your kernel with a processor type that is corresponding to the processor in your box. On gentoo, you already know that. With the other distributions, you have to install the kernel sources that correspond to your kernel in use, copy the .config file of this kernel into the kernel sources, run "make oldconfig" and "make menuconfig". In this menu, go to "Processor tape and features" -> "Processor family" and select the most appropriated family. Exit the menu, compile and install the kernel and its modules. For more information of the process of kernel compilation and installation, take a look at the forum of your distribution. It can be important distribution specific tricks that will make this easier and safer (in case of system upgrade and so on).
More about me
Hopefully, it is a life outside the computadores, the real life.
For now, I have one foot in Switzerland and one in Cuba.
Switzerland is an amazing country, but behind its goodies, it is very boring, peoples here are like in all the rich countries I know, obsessed by the money and so selfish. But it is here than I get at work 5 days a week. And for that, it is yet a good country.
Cuba is another amazing country. It is not only a tropical island, but also a socialist country. And the people here is truly kind and free. OK, they are not free to travel because they are too poor, but they are free to go at school at any age, they have free housing, free healthcare, phone and electricity prices are very very low, and they have many other advantages that are just unthinkable in a capitalist country. They can watch the TV canals from both Cuba and the US, same thing with the radio canals, and if they choose the Cuban's ones most of the time, it is because they are better. It is even 2 educational TV canals with subjects of all kinds, from the ground level up to the university level.
One time, I was walking into the country side, and I come into a very little village. Peoples was very surprised to see a tourist here, but very kind. The houses was simple, but in very good condition, it was electricity and a clean water system in all the houses, it was a common house with a TV and other amenities (as well than TV sets in the other houses), it was a little healthcare center done by a family doctor, and even a house with a popular university. I have never seen a so little village with so many facilities into a so rich country such as Switzerland. I was not in Switzerland but in Cuba.
I discussed with a lot of peoples, from a Police Commissioner or the director of one the biggest society in Cuba (the one that rent cars to the tourists), to ordinary peoples of all kinds, even with some rogue guys. I noticed 2 things unthinkable in Switzerland: all have a good education, are very open-minded and very critical of the Cuban system, all know their system better than most of us know the capitalism, and all of them don't want another system than the Cuban one. They are all very proud of what they are accomplishing in Cuba, and they all never forget that the first conquest of the Cuban revolution is the real independence of the Island.
Also, their criticism of their system is always constructive. The don't say "It's all bullshit" or non-understandable political talks. Instead, they said things like "This is not going well because this and that. We are aware of the problem, we want to correct it, and we are discussing the possible solutions. One is that, the other is this, and a few other peoples think like this. We must deepen the discussion in order to find the better solution." Sometime they add "because of the US blockade, we don't have the means to do it know and this is a wishful thinking".
Also, the nature of the Island is one of the most beautiful I have never seen. If you like to walk, prefer the winter, it is less hot.
In short, I am in love with Cuba, its inhabitants, their way of life, their choices, and also and of course with my future Cuban wife. She will be my third wife, and I hope the good and last one.