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author | kevans <kevans@FreeBSD.org> | 2018-04-13 03:32:18 +0000 |
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committer | kevans <kevans@FreeBSD.org> | 2018-04-13 03:32:18 +0000 |
commit | e815c44a7971dcfcd1f7fde4db8f92f11057f703 (patch) | |
tree | 077ea301d4968261753a4a622e24c95d60072307 | |
parent | 290514978463c1489e8a1914541f6babc3b49f8a (diff) | |
download | FreeBSD-src-e815c44a7971dcfcd1f7fde4db8f92f11057f703.zip FreeBSD-src-e815c44a7971dcfcd1f7fde4db8f92f11057f703.tar.gz |
MFC r319897-r319898, r319904: Improve yes' throughput
r319897: Improve yes' throughput
On my system, this brings up the throughput from ~20 to ~600 MiB/s.
Inspired by:
https://www.reddit.com/r/unix/comments/6gxduc/how_is_gnu_yes_so_fast/
r319898: Handle partial writes
r319904: style(9) fixes.
-rw-r--r-- | usr.bin/yes/yes.c | 35 |
1 files changed, 29 insertions, 6 deletions
diff --git a/usr.bin/yes/yes.c b/usr.bin/yes/yes.c index 2336d3f..404bf66 100644 --- a/usr.bin/yes/yes.c +++ b/usr.bin/yes/yes.c @@ -44,20 +44,43 @@ static const char rcsid[] = "$FreeBSD$"; #include <capsicum_helpers.h> #include <err.h> #include <stdio.h> +#include <string.h> +#include <unistd.h> int main(int argc, char **argv) { + char buf[8192]; + char y[2] = { 'y', '\n' }; + char * exp = y; + size_t buflen = 0; + size_t explen = sizeof(y); + size_t more; + ssize_t ret; if (caph_limit_stdio() < 0 || (cap_enter() < 0 && errno != ENOSYS)) err(1, "capsicum"); - if (argc > 1) - while (puts(argv[1]) != EOF) - ; - else - while (puts("y") != EOF) - ; + if (argc > 1) { + exp = argv[1]; + explen = strlen(exp) + 1; + exp[explen - 1] = '\n'; + } + + if (explen <= sizeof(buf)) { + while (buflen < sizeof(buf) - explen) { + memcpy(buf + buflen, exp, explen); + buflen += explen; + } + exp = buf; + explen = buflen; + } + + more = explen; + while ((ret = write(STDOUT_FILENO, exp + (explen - more), more)) > 0) + if ((more -= ret) == 0) + more = explen; + err(1, "stdout"); /*NOTREACHED*/ } |