Re: [PATCH] Enable parallelism in git submodule update.
- From
Jens Lehmann <jens.lehmann@web.de>
- Date
- Nov 3, 2012, 15:42 UTC
- Message-ID
- <50953B52.3070107@web.de>
- In-Reply-To
- <CAHOQ7J-e=KBOsjoeTWsf1f+LNgaAxN974-FXNMeOy7B-FR0wyg@mail.gmail.com>
Am 30.10.2012 19:11, schrieb Stefan Zager:
Show 8 quoted lines
> This is a refresh of a conversation from a couple of months ago. > > I didn't try to implement all the desired features (e.g., smart logic > for passing a -j parameter to recursive submodule invocations), but I > did address the one issue that Junio insisted on: the code makes a > best effort to detect whether xargs supports parallel execution on the > host platform, and if it doesn't, then it prints a warning and falls > back to serial execution.
I suspect not passing on --jobs recursively like you do here is the right thing to do, as that would give exponential growth of jobs with recursion depth, which makes no sense to me.
A still unsolved issue is the unstructured output from the different update jobs. It'll be hard (if not impossible) to see in what submodule which update took place (or failed). I think we should have a solution for that too (maybe one of those Heiko mentioned or something as simple as implying "-q"?).
Show 35 quoted lines
> Stefan > > On Tue, Oct 30, 2012 at 11:03 AM, <szager@google.com> wrote: >> The --jobs parameter may be used to set the degree of per-submodule >> parallel execution. > >> Signed-off-by: Stefan Zager <szager@google.com> >> --- >> Documentation/git-submodule.txt | 8 ++++++- >> git-submodule.sh | 40 ++++++++++++++++++++++++++++++++++++++- >> 2 files changed, 46 insertions(+), 2 deletions(-) >> >> diff --git a/Documentation/git-submodule.txt b/Documentation/git-submodule.txt >> index b4683bb..cb23ba7 100644 >> --- a/Documentation/git-submodule.txt >> +++ b/Documentation/git-submodule.txt >> @@ -14,7 +14,8 @@ SYNOPSIS >> 'git submodule' [--quiet] status [--cached] [--recursive] [--] [<path>...] >> 'git submodule' [--quiet] init [--] [<path>...] >> 'git submodule' [--quiet] update [--init] [-N|--no-fetch] [--rebase] >> - [--reference <repository>] [--merge] [--recursive] [--] [<path>...] >> + [--reference <repository>] [--merge] [--recursive] >> + [-j|--jobs [jobs]] [--] [<path>...] >> 'git submodule' [--quiet] summary [--cached|--files] [(-n|--summary-limit) <n>] >> [commit] [--] [<path>...] >> 'git submodule' [--quiet] foreach [--recursive] <command> >> @@ -146,6 +147,11 @@ If the submodule is not yet initialized, and you just want to use the >> setting as stored in .gitmodules, you can automatically initialize the >> submodule with the `--init` option. >> + >> +By default, each submodule is treated serially. You may specify a degree of >> +parallel execution with the --jobs flag. If a parameter is provided, it is >> +the maximum number of jobs to run in parallel; without a parameter, all jobs are >> +run in parallel. >> ++
The new "--jobs" option should be documented under "OPTIONS", (and maybe include that "--jobs 0" does the same as "--jobs" alone and that this is not supported on all platforms).
Show 88 quoted lines
>> If `--recursive` is specified, this command will recurse into the
>> registered submodules, and update any nested submodules within.
>> +
>> diff --git a/git-submodule.sh b/git-submodule.sh
>> index ab6b110..60a5f96 100755
>> --- a/git-submodule.sh
>> +++ b/git-submodule.sh
>> @@ -8,7 +8,7 @@ dashless=$(basename "$0" | sed -e 's/-/ /')
>> USAGE="[--quiet] add [-b branch] [-f|--force] [--reference <repository>] [--] <repository> [<path>]
>> or: $dashless [--quiet] status [--cached] [--recursive] [--] [<path>...]
>> or: $dashless [--quiet] init [--] [<path>...]
>> - or: $dashless [--quiet] update [--init] [-N|--no-fetch] [-f|--force] [--rebase] [--reference <repository>] [--merge] [--recursive] [--] [<path>...]
>> + or: $dashless [--quiet] update [--init] [-N|--no-fetch] [-f|--force] [--rebase] [--reference <repository>] [--merge] [--recursive] [-j|--jobs [jobs]] [--] [<path>...]
>> or: $dashless [--quiet] summary [--cached|--files] [--summary-limit <n>] [commit] [--] [<path>...]
>> or: $dashless [--quiet] foreach [--recursive] <command>
>> or: $dashless [--quiet] sync [--] [<path>...]"
>> @@ -500,6 +500,7 @@ cmd_update()
>> {
>> # parse $args after "submodule ... update".
>> orig_flags=
>> + jobs="1"
>> while test $# -ne 0
>> do
>> case "$1" in
>> @@ -518,6 +519,20 @@ cmd_update()
>> -r|--rebase)
>> update="rebase"
>> ;;
>> + -j|--jobs)
>> + case "$2" in
>> + ''|-*)
>> + jobs="0"
>> + ;;
>> + *)
>> + jobs="$2"
>> + shift
>> + ;;
>> + esac
>> + # Don't preserve this arg.
>> + shift
>> + continue
>> + ;;
>> --reference)
>> case "$2" in '') usage ;; esac
>> reference="--reference=$2"
>> @@ -551,11 +566,34 @@ cmd_update()
>> shift
>> done
>>
>> + # Correctly handle the case where '-q' came before 'update' on the command line.
>> + if test -n "$GIT_QUIET"
>> + then
>> + orig_flags="$orig_flags -q"
>> + fi
>> +
>> if test -n "$init"
>> then
>> cmd_init "--" "$@" || return
>> fi
>>
>> + if test "$jobs" != 1
>> + then
>> + if ( echo test | xargs -P "$jobs" true 2>/dev/null )
>> + then
>> + if ( echo test | xargs --max-lines=1 true 2>/dev/null ); then
>> + max_lines="--max-lines=1"
>> + else
>> + max_lines="-L 1"
>> + fi
>> + module_list "$@" | awk '{print $4}' |
>> + xargs $max_lines -P "$jobs" git submodule update $orig_flags
>> + return
>> + else
>> + echo "Warn: parallel execution is not supported on this platform."
>> + fi
>> + fi
>> +
>> cloned_modules=
>> module_list "$@" | {
>> err=
>> --
>> 1.7.7.3
>>
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