Pádraig Brady wrote: > To get the same benefits noticed with `sort` > http://git.savannah.gnu.org/gitweb/?p=coreutils.git;a=commit;h=dae35bac > I'm applying the same hint to all appropriate utils in the attached. ...
> Linux does quite well without this hint, and is getting better: > http://article.gmane.org/gmane.linux.kernel.mm/43753 > http://lkml.org/lkml/2010/2/3/27 > However I saw a small benefit on my system with > fast flash devices (around 5% less run time) and perhaps Nice! > the kernel can use this info in more sophisticated ways in future. ... > diff --git a/src/wc.c b/src/wc.c ... > @@ -211,6 +212,10 @@ wc (int fd, char const *file_x, struct fstatus *fstatus) > } > count_complicated = print_words || print_linelength; > > + /* Only advise the kernel of our access pattern if we need to read(). */ > + if (!count_bytes || count_chars || print_lines || count_complicated) > + fdadvise (fd, 0, 0, FADVISE_SEQUENTIAL); > + ... If you reword that comment /* Advise the kernel of our access pattern only if we will read(). */ it won't imply that advising is all it does in that case.