Timeline for Why is iterating over a file twice faster than reading it into memory and computing twice?
Current License: CC BY-SA 3.0
7 events
| when toggle format | what | by | license | comment | |
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| Mar 20, 2014 at 10:54 | comment | added | mikeserv | @Gilles, thanks for the thoughtful reply. Ive just been curious about page sizes lately. | |
| Mar 20, 2014 at 10:52 | comment | added | Gilles 'SO- stop being evil' | @mikeserv I haven't looked at the source to see how these programs choose the size. The most likely reasons to see 4096 would be a built-in constant or the st_blksize value for a pipe, which is 4096 on this machine (and I don't know if that's because it's the MMU page size). Bash's 128 would have to be a built-in constant. | |
| Mar 20, 2014 at 10:10 | comment | added | X Tian | Great work Gilles, tks. | |
| Mar 20, 2014 at 6:17 | comment | added | phunehehe | This is spot on Gilles! With zsh the second method is slightly faster on my machine. | |
| Mar 20, 2014 at 6:16 | vote | accept | phunehehe | ||
| Mar 20, 2014 at 4:32 | comment | added | mikeserv | Is the 4k figure page-size dependent? I mean, are tail and zsh both just mmaping syscalls? (Possibly that's incorrect terminology, though I hope not...) What's bash doing differently? | |
| Mar 20, 2014 at 2:37 | history | answered | Gilles 'SO- stop being evil' | CC BY-SA 3.0 |