svn commit: r319897 - head/usr.bin/yes
Pietro Cerutti
gahr at FreeBSD.org
Tue Jun 13 12:35:02 UTC 2017
Author: gahr (ports committer)
Date: Tue Jun 13 12:35:01 2017
New Revision: 319897
URL: https://svnweb.freebsd.org/changeset/base/319897
Log:
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/
Reviewed by: cognet
Approved by: cognet
Modified:
head/usr.bin/yes/yes.c
Modified: head/usr.bin/yes/yes.c
==============================================================================
--- head/usr.bin/yes/yes.c Tue Jun 13 12:07:18 2017 (r319896)
+++ head/usr.bin/yes/yes.c Tue Jun 13 12:35:01 2017 (r319897)
@@ -44,20 +44,42 @@ 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);
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)
- ;
+ {
+ 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;
+ }
+
+ while (write(STDOUT_FILENO, exp, explen) > 0)
+ ;
+
err(1, "stdout");
/*NOTREACHED*/
}
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