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
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commit
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Notes:
svn2git
2020-12-20 02:59:44 +00:00
svn path=/head/; revision=319897
@ -44,20 +44,42 @@ static const char rcsid[] = "$FreeBSD$";
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#include <capsicum_helpers.h>
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#include <err.h>
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#include <stdio.h>
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#include <string.h>
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#include <unistd.h>
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int
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main(int argc, char **argv)
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{
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char buf[8192];
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char y[2] = { 'y', '\n' };
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char * exp = y;
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size_t buflen = 0;
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size_t explen = sizeof(y);
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if (caph_limit_stdio() < 0 || (cap_enter() < 0 && errno != ENOSYS))
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err(1, "capsicum");
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if (argc > 1)
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while (puts(argv[1]) != EOF)
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;
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else
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while (puts("y") != EOF)
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{
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exp = argv[1];
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explen = strlen(exp) + 1;
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exp[explen - 1] = '\n';
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}
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if (explen <= sizeof(buf))
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{
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while (buflen < sizeof(buf) - explen)
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{
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memcpy(buf + buflen, exp, explen);
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buflen += explen;
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}
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exp = buf;
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explen = buflen;
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}
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while (write(STDOUT_FILENO, exp, explen) > 0)
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;
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err(1, "stdout");
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/*NOTREACHED*/
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}
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