2bae1ab6a5
When reading the code I had to stop, say "ok, what does *these* modifications of strl*() do? Pull out grep. Oh, not in add/, maybe above in ../lib/? Yep. So what do they do? Comments above them are misleading, guess I'll have to read the code. Oh, they just test strl* against the size and return the result of the test. Now I can continue to read the code I was. The uses of s_strl*() then test that result and errx()'s. Lets think about the "optimized" code I am removing: In general the compiler pushes the three args to strl* onto the stack and calls s_strl*. s_strl* has to indirectly access 3 args from the stack. Then push them on the stack a 2nd time for the real strl* call. s_strl* then pops the return from strl* off the stack; or moves it from the register it was returned in, to the register where tests can happen. s_strl* then pops the three arguments to strl*. Perform the test, push the result of the test, or move it from the result register to the return value register. The caller to s_strl* now has to either pop the return value of s_strl* or move it from the return value register to the test register. The caller then pops the three args to s_strl* off the stack (the same args that s_strl* itself had to pop off after the real call to strl*). The s_strl* caller then performs a simular test to what has already been done, and conditionally jumps. By doing things this way, we've given the compiler optimizer less to work with. Also, please don't forget the that call to s_strl* has possibly jumped to code not in the cache due to being far away from the calling code, thus causing a pipeline stall. So where is the "optimization" from s_strl*? It isn't code clarity. It isn't code execution speed. It isn't code size either. |
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| .. | ||
| add | ||
| create | ||
| delete | ||
| info | ||
| lib | ||
| sign | ||
| update | ||
| version | ||
| Makefile | ||
| Makefile.inc | ||
| README | ||
| tkpkg | ||
This is the pkg_install suite of tools for doing maintainance of software "packages". More documentation is available in the man pages for each individual command. This code was written by Jordan Hubbard for FreeBSD, snatched and mildly reshaped by John Kohl in NetBSD and the changes taken back into FreeBSD again by Jordan, who then proceeded to add another couple of dozen features on top. Whee! :-)