Re: [PATCH v2 2/4] fsmonitor: Don't bother pretty-printing JSON from watchman
From: Ben Peart <hidden>
Date: 2017-10-26 20:05:19
On 10/25/2017 9:31 PM, Alex Vandiver wrote:
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.
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#!/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 <redacted> --- 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.
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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";