#29356: atlas @3.9.37 build failure - hangs with xztfc using 100% CPU ---------------------------------+------------------------------------------ Reporter: alan@… | Owner: jameskyle@… Type: defect | Status: closed Priority: Normal | Milestone: Component: ports | Version: 1.9.2 Resolution: invalid | Keywords: Port: atlas | ---------------------------------+------------------------------------------ Changes (by vince@…): * status: new => closed * resolution: => invalid Comment: ATLAS compiles pretty fast in 64-bit mode. It takes something like 15 min on my 3-year old MacBook Core2Duo. But, you're right, if you build the 32-bit version (in your case, that would mean universal), it can be very slow. That's because, in 32-bit mode, Atlas explores a lot of different parameters for each routine it compiles (eg. use of X87 vs SSE/SSE2/SSE3, spacing of data to optimize cache fetch/prefetch, and so on). Unfortunately, since about every routine is already written in assembler, there is little gain to be expected from one processor to the other. That explains why it takes, in 32-bit mode, about the same time with a basic Core processor than with a new Sandy bridge CPU. -- Ticket URL: <https://trac.macports.org/ticket/29356#comment:6> MacPorts <http://www.macports.org/> Ports system for Mac OS