Re: [PATCH v7 24/29] t/perf/p7519: speed up test on Windows

> From: Jeff Hostetler <jeffhost@microsoft.com>
>
> Change p7519 to use `test_seq` and `xargs` rather than a `for` loop
> to touch thousands of files.  This takes minutes off of test runs
> on Windows because of process creation overhead.
>
> Signed-off-by: Jeff Hostetler <jeffhost@microsoft.com>
> Signed-off-by: Junio C Hamano <gitster@pobox.com>
> ---
>  t/perf/p7519-fsmonitor.sh | 32 ++++++++++++++++++++------------
>  1 file changed, 20 insertions(+), 12 deletions(-)
>
> diff --git a/t/perf/p7519-fsmonitor.sh b/t/perf/p7519-fsmonitor.sh
> index c8be58f3c76..0611e533951 100755
> --- a/t/perf/p7519-fsmonitor.sh
> +++ b/t/perf/p7519-fsmonitor.sh
> @@ -72,7 +72,7 @@ then
>  	fi
>  fi
>  
> -trace_start() {
> +trace_start () {
>  	if test -n "$GIT_PERF_7519_TRACE"
>  	then
>  		name="$1"
> @@ -91,13 +91,20 @@ trace_start() {
>  	fi
>  }
>  
> -trace_stop() {
> +trace_stop () {
>  	if test -n "$GIT_PERF_7519_TRACE"
>  	then
>  		unset GIT_TRACE2_PERF
>  	fi
>  }

> +touch_files () {
> +	n=$1
> +	d="$n"_files
> +
> +	(cd $d ; test_seq 1 $n | xargs touch )

> +}
> +
>  test_expect_success "one time repo setup" '
>  	# set untrackedCache depending on the environment
>  	if test -n "$GIT_PERF_7519_UNTRACKED_CACHE"
> @@ -119,10 +126,11 @@ test_expect_success "one time repo setup" '
>  	fi &&
>  
>  	mkdir 1_file 10_files 100_files 1000_files 10000_files &&
> -	for i in $(test_seq 1 10); do touch 10_files/$i || return 1; done &&
> -	for i in $(test_seq 1 100); do touch 100_files/$i || return 1; done &&
> -	for i in $(test_seq 1 1000); do touch 1000_files/$i || return 1; done &&
> -	for i in $(test_seq 1 10000); do touch 10000_files/$i || return 1; done &&
> +	: 1_file directory should be left empty &&
> +	touch_files 10 &&
> +	touch_files 100 &&
> +	touch_files 1000 &&
> +	touch_files 10000 &&
>  	git add 1_file 10_files 100_files 1000_files 10000_files &&
>  	git commit -qm "Add files" &&
>  
> @@ -133,7 +141,7 @@ test_expect_success "one time repo setup" '
>  	fi
>  '
>  
> -setup_for_fsmonitor() {
> +setup_for_fsmonitor () {
>  	# set INTEGRATION_SCRIPT depending on the environment
>  	if test -n "$INTEGRATION_PATH"
>  	then
> @@ -173,7 +181,7 @@ test_perf_w_drop_caches () {
>  	test_perf "$@"
>  }
>  
> -test_fsmonitor_suite() {
> +test_fsmonitor_suite () {