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* src/yes.c (main): Output 'y' not '-'.
* tests/misc/yes.sh: Add a test for default output.
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* src/yes.c (main): For large inputs only write a single
diagnostic for write errors.
* tests/misc/yes.sh: Test when /dev/full is available.
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Run "make update-copyright" and then...
* gnulib: Update to latest with copyright year adjusted.
* tests/init.sh: Sync with gnulib to pick up copyright year.
* bootstrap: Likewise.
* tests/sample-test: Adjust to use the single most recent year.
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programs may not be built due to missing system dependencies,
or any program can be excluded at configure time with
--enable-no-install-program. So ensure we're not testing the
system versions in these cases.
* init.cfg (print_ver_): Call require_built_ first.
* tests/misc/tty-eof.pl: Skip programs not built.
* tests/Coreutils.pm (run_tests): Likewise.
* tests/misc/ls-misc.pl: Use 'env test' rather than abs path.
* tests/misc/test-diag.pl: Likewise.
* tests/local.mk: Adjust include order for dependencies.
* tests/misc/arch.sh: Remove redundant calls to require_built_.
* tests/misc/chroot-fail.sh: Likewise.
* tests/misc/groups-dash.sh: Likewise.
* tests/misc/groups-version.sh: Likewise.
* tests/misc/stdbuf.sh: Likewise.
* tests/cp/acl.sh: Remove problematic call to print_ver_ [gs]etfacl.
* tests/mv/acl.sh: Likewise.
* cfg.mk (sc_env_test_dependencies): A new syntax check to enforce
specifying dependencies with print_ver_ for programs
specified through the env command.
* du/bigtime.sh: Add new print_ver_ dependencies.
* du/max-depth.sh: Likewise.
* dd/ascii.sh: Likewise.
* tests/ls/capability.sh: Likewise.
* tests/ls/root-rel-symlink-color.sh: Likewise.
* tests/misc/chroot-fail.sh: Likewise.
* tests/misc/readlink-fp-loop.sh: Likewise.
* tests/misc/sort-debug-keys.sh: Likewise.
* tests/readlink/can-e.sh: Likewise.
* tests/readlink/can-f.sh: Likewise.
* tests/readlink/can-m.sh: Likewise.
* tests/tail-2/inotify-race.sh: Likewise.
* tests/tail-2/inotify-race2.sh: Likewise.
* tests/touch/no-create-missing.sh: Likewise.
* tests/touch/no-dereference.sh: Likewise.
* tests/misc/printenv.sh: Tweak to avoid syntax check trigger.
* tests/misc/help-version.sh: Likewise.
* tests/misc/yes.sh: Likewise.
* tests/misc/printf-quote.sh: Use previously unused $prog.
* configure.ac (EXTRA_MANS): Add $gl_no_install_prog to the list
so that check-x-vs-1 syntax check is satisfied.
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* src/yes.c (main): Even when the internal buffer isn't large enough,
output what we've buffered already, and interate over the rest.
This improves the performance in the edge case where there are
many small arguments that overflow the buffer.
* tests/misc/yes.sh: Add a test case for the many small arguments case.
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yes(1) may be used to generate repeating patterns of text
for test inputs etc., so adjust to be more efficient.
Profiling the case where yes(1) is outputting small items
through stdio (which was the default case), shows the overhead
of continuously processing small items in main() and in stdio:
$ yes >/dev/null & perf top -p $!
31.02% yes [.] main
27.36% libc-2.20.so [.] _IO_file_xsputn@@GLIBC_2.2.5
14.51% libc-2.20.so [.] fputs_unlocked
13.50% libc-2.20.so [.] strlen
10.66% libc-2.20.so [.] __GI___mempcpy
1.98% yes [.] fputs_unlocked@plta
Sending more data per stdio call improves the situation,
but still, there is significant stdio overhead due to memory copies,
and the repeated string length checking:
$ yes "`echo {1..1000}`" >/dev/null & perf top -p $!
42.26% libc-2.20.so [.] __GI___mempcpy
17.38% libc-2.20.so [.] strlen
5.21% [kernel] [k] __srcu_read_lock
4.58% [kernel] [k] __srcu_read_unlock
4.27% libc-2.20.so [.] _IO_file_xsputn@@GLIBC_2.2.5
2.50% libc-2.20.so [.] __GI___libc_write
2.45% [kernel] [k] system_call
2.40% [kernel] [k] system_call_after_swapgs
2.27% [kernel] [k] vfs_write
2.09% libc-2.20.so [.] _IO_do_write@@GLIBC_2.2.5
2.01% [kernel] [k] fsnotify
1.95% libc-2.20.so [.] _IO_file_write@@GLIBC_2.2.5
1.44% yes [.] main
We can avoid all stdio overhead by building up the buffer
_once_ and outputting that, and the profile below shows
the bottleneck moved to the kernel:
$ src/yes >/dev/null & perf top -p $!
15.42% [kernel] [k] __srcu_read_lock
12.98% [kernel] [k] __srcu_read_unlock
9.41% libc-2.20.so [.] __GI___libc_write
9.11% [kernel] [k] vfs_write
8.35% [kernel] [k] fsnotify
8.02% [kernel] [k] system_call
5.84% [kernel] [k] system_call_after_swapgs
4.54% [kernel] [k] __fget_light
3.98% [kernel] [k] sys_write
3.65% [kernel] [k] selinux_file_permission
3.44% [kernel] [k] rw_verify_area
2.94% [kernel] [k] __fsnotify_parent
2.76% [kernel] [k] security_file_permission
2.39% yes [.] main
2.17% [kernel] [k] __fdget_pos
2.13% [kernel] [k] sysret_check
0.81% [kernel] [k] write_null
0.36% yes [.] write@plt
Note this change also ensures that yes(1) will only write
complete lines for lines shorter than BUFSIZ.
* src/yes.c (main): Build up a BUFSIZ buffer of lines,
and output that, rather than having stdio process each item.
* tests/misc/yes.sh: Add a new test for various buffer sizes.
* tests/local.mk: Reference the new test.
Fixes http://bugs.gnu.org/20029
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