Does ccache take care of the optimization applied to the compiled code?
Linux - SoftwareThis forum is for Software issues.
Having a problem installing a new program? Want to know which application is best for the job? Post your question in this forum.
Notices
Welcome to LinuxQuestions.org, a friendly and active Linux Community.
You are currently viewing LQ as a guest. By joining our community you will have the ability to post topics, receive our newsletter, use the advanced search, subscribe to threads and access many other special features. Registration is quick, simple and absolutely free. Join our community today!
Note that registered members see fewer ads, and ContentLink is completely disabled once you log in.
If you have any problems with the registration process or your account login, please contact us. If you need to reset your password, click here.
Having a problem logging in? Please visit this page to clear all LQ-related cookies.
Get a virtual cloud desktop with the Linux distro that you want in less than five minutes with Shells! With over 10 pre-installed distros to choose from, the worry-free installation life is here! Whether you are a digital nomad or just looking for flexibility, Shells can put your Linux machine on the device that you want to use.
Exclusive for LQ members, get up to 45% off per month. Click here for more info.
Does ccache take care of the optimization applied to the compiled code?
Hi,
I have recently began compiling custom-kernels and have come across ccache and distcc, two excellent tool to speed up the compilation. I was wondering whether ccache takes care that I had specified (or unspecified) optimizations like -Os, -O1, -O2, etc.? In other words, if I first apply, say, -O2 optimization and allow ccache to cache the optimized object file, and later if I compile the same code using, say, -Os, will ccache use the previously cached data, and thus ignore my new settings?
Ideally, ccache should allow the code to be completely recompiled with the new optimization settings, and then cache the new files, along with the previous ones, so that if I ever want to compile the code using either -Os or -O2 optimization, I would not have to wait for the complete code to be compiled again. Is that the case?
I have recently began compiling custom-kernels and have come across ccache and distcc, two excellent tool to speed up the compilation. I was wondering whether ccache takes care that I had specified (or unspecified) optimizations like -Os, -O1, -O2, etc.? In other words, if I first apply, say, -O2 optimization and allow ccache to cache the optimized object file, and later if I compile the same code using, say, -Os, will ccache use the previously cached data, and thus ignore my new settings?
First of all, here is a reference to a description of how ccache works. That should answer most of your future upcoming questions ;-)
To answer your specific question: ccache does not try to be more clever than you are. If you specify new options (e.g. -Os), ccache will not be able to find any cached results in its cache (because you only cached -O2) so that ccache will recompile your code.
Quote:
Originally Posted by dhruv17singhal
Ideally, ccache should allow the code to be completely recompiled with the new optimization settings, and then cache the new files, along with the previous ones, so that if I ever want to compile the code using either -Os or -O2 optimization, I would not have to wait for the complete code to be compiled again. Is that the case?
Yes, think so. Unless you clear the cache, you'll keep all the previous results.
LinuxQuestions.org is looking for people interested in writing
Editorials, Articles, Reviews, and more. If you'd like to contribute
content, let us know.