Re: [PATCH v2 2/4] fsmonitor: Don't bother pretty-printing JSON from watchman
- From
Ben Peart <peartben@gmail.com>
- Date
- Oct 26, 2017, 20:05 UTC
- Message-ID
- <9bd24b15-6232-1afd-abbe-02870c51c7ad@gmail.com>
- In-Reply-To
- <42fd8bccb78992a2894e711e057230a673891628.1508981451.git.alexmv@dropbox.com>
On 10/25/2017 9:31 PM, Alex Vandiver wrote:
Show 5 quoted lines
> This provides modest performance savings. Benchmarking with the > following program, with and without `--no-pretty`, we find savings of > 23% (0.316s -> 0.242s) in the git repository, and savings of 8% (5.24s > -> 4.86s) on a large repository with 580k files in the working copy. >
Given this patch series is all about speed, it's good to see *any* wins - especially those that don't impact functionality at all. The performance win of --no-pretty is greater than I expected.
Show 44 quoted lines
> #!/usr/bin/perl
>
> use strict;
> use warnings;
> use IPC::Open2;
>
> my $pid = open2(\*CHLD_OUT, \*CHLD_IN, "watchman -j @ARGV")
> or die "open2() failed: $!\n" .
> "Falling back to scanning...\n";
>
> my $query = qq|["query", "$ENV{PWD}", {}]|;
>
> print CHLD_IN $query;
> close CHLD_IN;
> my $response = do {local $/; <CHLD_OUT>};
>
> my $json_pkg;
> eval {
> require JSON::XSomething;
> $json_pkg = "JSON::XSomething";
> 1;
> } or do {
> require JSON::PP;
> $json_pkg = "JSON::PP";
> };
>
> my $o = $json_pkg->new->utf8->decode($response);
>
> Signed-off-by: Alex Vandiver <alexmv@dropbox.com>
> ---
> t/t7519/fsmonitor-watchman | 2 +-
> templates/hooks--fsmonitor-watchman.sample | 2 +-
> 2 files changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/t/t7519/fsmonitor-watchman b/t/t7519/fsmonitor-watchman
> index a3e30bf54..79f24325c 100755
> --- a/t/t7519/fsmonitor-watchman
> +++ b/t/t7519/fsmonitor-watchman
> @@ -50,7 +50,7 @@ launch_watchman();
>
> sub launch_watchman {
>
> - my $pid = open2(\*CHLD_OUT, \*CHLD_IN, 'watchman -j')
> + my $pid = open2(\*CHLD_OUT, \*CHLD_IN, 'watchman -j --no-pretty')Since this is a test script performance isn't critical. This version of the integration script logs the response to a file in .git/watchman-response.json and is much more human readable without the "--no-pretty." As such, I'd leave this one pretty.
Show 13 quoted lines
> or die "open2() failed: $!\n" .
> "Falling back to scanning...\n";
>
> diff --git a/templates/hooks--fsmonitor-watchman.sample b/templates/hooks--fsmonitor-watchman.sample
> index 9eba8a740..9a082f278 100755
> --- a/templates/hooks--fsmonitor-watchman.sample
> +++ b/templates/hooks--fsmonitor-watchman.sample
> @@ -49,7 +49,7 @@ launch_watchman();
>
> sub launch_watchman {
>
> - my $pid = open2(\*CHLD_OUT, \*CHLD_IN, 'watchman -j')
> + my $pid = open2(\*CHLD_OUT, \*CHLD_IN, 'watchman -j --no-pretty')No human will see this response so the faster --no-pretty option makes sense.
> or die "open2() failed: $!\n" . > "Falling back to scanning...\n"; > >