Author: kevans
Date: Fri Apr 13 03:32:18 2018
New Revision: 332464
URL: https://svnweb.freebsd.org/changeset/base/332464
Log:
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.
Modified:
stable/11/usr.bin/yes/yes.c
Directory Properties:
stable/11/ (props changed)
Modified: stable/11/usr.bin/yes/yes.c
==============================================================================
--- stable/11/usr.bin/yes/yes.c Fri Apr 13 03:30:10 2018 (r332463)
+++ stable/11/usr.bin/yes/yes.c Fri Apr 13 03:32:18 2018 (r332464)
@@ -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*/
}
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