You can override the reference branch with the --origin=mysourcebranch option.
+The Perforce changelists will be created with the user who ran git-p4. If you
+use --preserve-user then git-p4 will attempt to create Perforce changelists
+with the Perforce user corresponding to the git commit author. You need to
+have sufficient permissions within Perforce, and the git users need to have
+Perforce accounts. Permissions can be granted using 'p4 protect'.
+
If a submit fails you may have to "p4 resolve" and submit manually. You can
continue importing the remaining changes with
both filter the files cloned by git and set the directory layout as
specified in the client (this implies --keep-path style semantics).
+git-p4.skipSubmitEdit
+
+ git config [--global] git-p4.skipSubmitEdit false
+
+Normally, git-p4 invokes an editor after each commit is applied so
+that you can make changes to the submit message. Setting this
+variable to true will skip the editing step, submitting the change as is.
+
+git-p4.skipSubmitEditCheck
+
+ git config [--global] git-p4.skipSubmitEditCheck false
+
+After the editor is invoked, git-p4 normally makes sure you saved the
+change description, as an indication that you did indeed read it over
+and edit it. You can quit without saving to abort the submit (or skip
+this change and continue). Setting this variable to true will cause
+git-p4 not to check if you saved the change description. This variable
+only matters if git-p4.skipSubmitEdit has not been set to true.
+
+git-p4.preserveUser
+
+ git config [--global] git-p4.preserveUser false
+
+If true, attempt to preserve user names by modifying the p4 changelists. See
+the "--preserve-user" submit option.
+
+git-p4.allowMissingPerforceUsers
+
+ git config [--global] git-p4.allowMissingP4Users false
+
+If git-p4 is setting the perforce user for a commit (--preserve-user) then
+if there is no perforce user corresponding to the git author, git-p4 will
+stop. With allowMissingPerforceUsers set to true, git-p4 will use the
+current user (i.e. the behavior without --preserve-user) and carry on with
+the perforce commit.
+
+git-p4.skipUserNameCheck
+
+ git config [--global] git-p4.skipUserNameCheck false
+
+When submitting, git-p4 checks that the git commits are authored by the current
+p4 user, and warns if they are not. This disables the check.
+
+git-p4.detectRenames
+
+Detect renames when submitting changes to Perforce server. Will enable -M git
+argument. Can be optionally set to a number representing the threshold
+percentage value of the rename detection.
+
+ git config [--global] git-p4.detectRenames true
+ git config [--global] git-p4.detectRenames 50
+
+git-p4.detectCopies
+
+Detect copies when submitting changes to Perforce server. Will enable -C git
+argument. Can be optionally set to a number representing the threshold
+percentage value of the copy detection.
+
+ git config [--global] git-p4.detectCopies true
+ git config [--global] git-p4.detectCopies 80
+
+git-p4.detectCopiesHarder
+
+Detect copies even between files that did not change when submitting changes to
+Perforce server. Will enable --find-copies-harder git argument.
+
+ git config [--global] git-p4.detectCopies true
+
+git-p4.branchUser
+
+Only use branch specifications defined by the selected username.
+
+ git config [--global] git-p4.branchUser username
+
+git-p4.branchList
+
+List of branches to be imported when branch detection is enabled.
+
+ git config [--global] git-p4.branchList main:branchA
+ git config [--global] --add git-p4.branchList main:branchB
+
Implementation Details...
=========================