On 6/13/2017 5:35 AM, Pietro Cerutti wrote: > 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];
8192 feels arbitrary but it has a purpose. Shouldn't it be based on
PAGE_SIZE or something?
> + char y[2] = { 'y', '\n' };
> + char * exp = y;
> + size_t buflen = 0;
> + size_t explen = sizeof(y);
More style bugs here
>
> 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*/
> }
>
--
Regards,
Bryan Drewery
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