Messages in this thread | | | Date | Sun, 12 Jul 1998 09:46:13 -0400 (EDT) | From | "C. Scott Ananian" <> | Subject | new time.c code: a caveat |
| |
Note that *checking* the new time.c code for bugs is actually extremely difficult: not that many things use sub-second time accuracy, and those that do are often difficult to monitor. In many cases monotony is sufficient to keep any problems from showing up. The old time.c code would warp ahead to the next jiffy on machines with slowed TSCs, yielding *no* *sub-jiffy* *accuracy* *at* *all* and to my knowledge no one ever noticed this until things got so bad that a kernel divide-by-zero error finally resulted (and even then, the kernel trapped and logged the exception and continued merrily on).
So, before/as code comes in to revamp time.c, the big question ought to be testability. It is not trivial to make some sort of primitive test suite, but it ought to be done anyway. How else do we know the proposed codes work *at all*? --Scott [as before, please make sure 'time.c' is somewhere in the subject of your reponse if you'd like me to be able to see it] @ @ =-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-oOO-(_)-OOo-=-=-=-=-= C. Scott Ananian: cananian@lcs.mit.edu / Declare the Truth boldly and Laboratory for Computer Science/Crypto / without hindrance. Massachusetts Institute of Technology /META-PARRESIAS AKOLUTOS:Acts 28:31 -.-. .-.. .. ..-. ..-. --- .-. -.. ... -.-. --- - - .- -. .- -. .. .- -. PGP key available via finger and from http://www.pdos.lcs.mit.edu/~cananian
- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.rutgers.edu Please read the FAQ at http://www.altern.org/andrebalsa/doc/lkml-faq.html
| |