Messages in this thread |  | | Date | Sat, 13 Oct 2001 15:19:16 -0700 (PDT) | From | Linus Torvalds <> | Subject | Re: Security question: "Text file busy" overwriting executables but not shared libraries? |
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On Sat, 13 Oct 2001, Jamie Lokier wrote: > > There are applications (GCC comes to mind) which are using mmap() to > read files now because it is measurably faster than read(), for > sufficiently large source files. > > I don't know where the optimal costs lie.
The gcc people tested it, and their cut-off point is at 30kB or so. Anything smaller than that is faster to just "read()".
Now, that's a traditional mmap(), though, which has more overhead than a "read-with-PAGE_COPY" would have. The pure mmap() approach has the actual page fault overhead too, along with having to do "fstat()" and "munmap()".
Linus
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