From mboxrd@z Thu Jan 1 00:00:00 1970 From: Petr Baudis Subject: Re: [PATCH] bash completion: Improve responsiveness of git-log completion Date: Sun, 13 Jul 2008 06:02:48 +0200 Message-ID: <20080713040248.GG10151@machine.or.cz> References: <20080713023742.GA31760@spearce.org> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: Junio C Hamano , git@vger.kernel.org To: "Shawn O. Pearce" X-From: git-owner@vger.kernel.org Sun Jul 13 06:11:42 2008 Return-path: Envelope-to: gcvg-git-2@gmane.org Received: from vger.kernel.org ([209.132.176.167]) by lo.gmane.org with esmtp (Exim 4.50) id 1KHsw1-0004qO-IC for gcvg-git-2@gmane.org; Sun, 13 Jul 2008 06:11:41 +0200 Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1750752AbYGMECv (ORCPT ); Sun, 13 Jul 2008 00:02:51 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1750751AbYGMECv (ORCPT ); Sun, 13 Jul 2008 00:02:51 -0400 Received: from w241.dkm.cz ([62.24.88.241]:60604 "EHLO machine.or.cz" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750741AbYGMECu (ORCPT ); Sun, 13 Jul 2008 00:02:50 -0400 Received: by machine.or.cz (Postfix, from userid 2001) id B0523393B32A; Sun, 13 Jul 2008 06:02:48 +0200 (CEST) Content-Disposition: inline In-Reply-To: <20080713023742.GA31760@spearce.org> User-Agent: Mutt/1.5.16 (2007-06-09) Sender: git-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: git@vger.kernel.org Archived-At: On Sun, Jul 13, 2008 at 02:37:42AM +0000, Shawn O. Pearce wrote: > Junio noticed the bash completion has been taking a long time lately. > Petr Baudis tracked it down to 72e5e989b ("bash: Add space after > unique command name is completed."). Tracing the code showed > we spent significant time inside of this loop within __gitcomp, > due to the string copying overhead. > > [28.146109654] _git common over > [28.164791148] gitrefs in > [28.280302268] gitrefs dir out > [28.300939737] gitcomp in > [28.308378112] gitcomp pre-case > * [28.313407453] gitcomp iter in > * [28.701270296] gitcomp iter out > [28.713370786] out normal > > Since __git_refs avoids this string copying by forking and using > echo we use the same trick here when we need to finish generating > the names for the caller. > > Signed-off-by: Shawn O. Pearce I spent quite some time trying to optimize the run by heavy use of bash arrays (either just in __gitcomp() and at later stage reusing __git_refs() array within __gitcomp()), but it turned out I have made few simple mistakes and in the end, the array is slower than Shawn's approach - when reusing the array, the difference is even bigger. I think that if a[i]=x is slower than echo x, bash is doing something real weird, but that seems to be the case. Someone might find my simple and noisy benchmarker useful: diff --git a/contrib/completion/git-completion.bash b/contrib/completion/git-completion.bash index 27332ed..31f97c1 100755 --- a/contrib/completion/git-completion.bash +++ b/contrib/completion/git-completion.bash @@ -45,6 +45,18 @@ # git@vger.kernel.org # + +benchmark_last=0 +benchmark_delta=0 +benchmark () +{ + #return + local now=$(date +%S%N) + benchmark_diff=$(echo "($now-$benchmark_last)/1000000-($benchmark_delta)"|bc) + echo "[+${benchmark_diff}ms] $*" >&2 + benchmark_last=$now +} + __gitdir () { if [ -z "$1" ]; then @@ -116,6 +128,7 @@ __git_ps1 () __gitcomp () { + benchmark "gitcomp start" local all c s=$'\n' IFS=' '$'\t'$'\n' local cur="${COMP_WORDS[COMP_CWORD]}" if [ $# -gt 2 ]; then @@ -138,6 +151,7 @@ __gitcomp () esac IFS=$s COMPREPLY=($(compgen -P "$2" -W "$all" -- "$cur")) + benchmark "gitcomp end" return } @@ -185,12 +199,16 @@ __git_tags () __git_refs () { + benchmark "gitrefs in" local cmd i is_hash=y dir="$(__gitdir "$1")" if [ -d "$dir" ]; then if [ -e "$dir/HEAD" ]; then echo HEAD; fi - for i in $(git --git-dir="$dir" \ + benchmark "gitrefs dir a" + local a=($(git --git-dir="$dir" \ for-each-ref --format='%(refname)' \ - refs/tags refs/heads refs/remotes); do + refs/tags refs/heads refs/remotes)) + benchmark "gitrefs dir r" + for i in "${a[@]}"; do case "$i" in refs/tags/*) echo "${i#refs/tags/}" ;; refs/heads/*) echo "${i#refs/heads/}" ;; @@ -198,6 +216,7 @@ __git_refs () *) echo "$i" ;; esac done + benchmark "gitrefs dir out" return fi for i in $(git ls-remote "$dir" 2>/dev/null); do @@ -210,6 +229,7 @@ __git_refs () n,*) is_hash=y; echo "$i" ;; esac done + benchmark "gitrefs out" } __git_refs2 () @@ -324,7 +344,9 @@ __git_complete_revlist () __gitcomp "$cur." ;; *) + benchmark "revlist simple in" __gitcomp "$(__git_refs)" + benchmark "revlist simple out" ;; esac } @@ -756,6 +778,8 @@ _git_log () { __git_has_doubledash && return + benchmark "doubledash over" + local cur="${COMP_WORDS[COMP_CWORD]}" case "$cur" in --pretty=*) @@ -791,6 +815,7 @@ _git_log () return ;; esac + benchmark "gitcomp over" __git_complete_revlist } @@ -1303,6 +1328,9 @@ _git () { local i c=1 command __git_dir + benchmark "in"; benchmark_delta=0 + benchmark "in netto"; benchmark_delta=$benchmark_diff + while [ $c -lt $COMP_CWORD ]; do i="${COMP_WORDS[c]}" case "$i" in @@ -1314,6 +1342,8 @@ _git () c=$((++c)) done + #[ "$__git_dir" ] || __git_dir="$(__gitdir)" + if [ -z "$command" ]; then case "${COMP_WORDS[COMP_CWORD]}" in --*=*) COMPREPLY=() ;; @@ -1330,12 +1360,16 @@ _git () ;; *) __gitcomp "$(__git_commands) $(__git_aliases)" ;; esac + + benchmark "out cut $(date +%S.%N)" return fi local expansion=$(__git_aliased_command "$command") [ "$expansion" ] && command="$expansion" + benchmark "mark common" + case "$command" in am) _git_am ;; add) _git_add ;; @@ -1374,6 +1408,8 @@ _git () whatchanged) _git_log ;; *) COMPREPLY=() ;; esac + + benchmark "out normal" } _gitk ()