sync: rework --jobs to provide better defaults

For --jobs-network, the logic is now:
* If the user specifies --jobs-network, use that.
* Else, if the user specifies --jobs, use that.
* Else, if the manifest specifies sync-j, use that.
* Else, default to 1.
Then we limit the jobs count based on the softlimit RLIMIT_NOFILE.

For --jobs-checkout, the logic is now:
* If the user specifies --jobs-checkout, use that.
* Else, if the user specifies --jobs, use that.
* Else, if the manifest specifies sync-j, use that.
* Else, default to DEFAULT_LOCAL_JOBS which is based on user's ncpus.
Then we limit the jobs count based on the softlimit RLIMIT_NOFILE.

For garbage collecting, the logic is now:
* If the user specifies --jobs, use that.
* Else, if the manifest specifies sync-j, use that.
* Else, default to the user's ncpus.
Then we limit the jobs count based on the softlimit RLIMIT_NOFILE.

Having to factor in the manifest settings makes this more complicated
which is why we delay processing of defaults until after we've synced
the manifest projects.

Bug: http://b/239712300
Change-Id: Id27cda63c76c156f1d63f6a20cb2c4ceeb3d547c
Reviewed-on: https://gerrit-review.googlesource.com/c/git-repo/+/341394
Tested-by: Mike Frysinger <vapier@google.com>
Reviewed-by: LaMont Jones <lamontjones@google.com>

1 files changed, 4 insertions, 4 deletions

diff --git a/manifest_xml.py b/manifest_xml.py
index 12614c64..ee513a7e 100644
--- a/manifest_xml.py
+++ b/manifest_xml.py
@@ -123,7 +123,7 @@ class _Default(object):
   destBranchExpr = None
   upstreamExpr = None
   remote = None
-  sync_j = 1
+  sync_j = None
   sync_c = False
   sync_s = False
   sync_tags = True
@@ -548,7 +548,7 @@ https://gerrit.googlesource.com/git-repo/+/HEAD/docs/manifest-format.md
     if d.upstreamExpr:
       have_default = True
       e.setAttribute('upstream', d.upstreamExpr)
-    if d.sync_j > 1:
+    if d.sync_j is not None:
       have_default = True
       e.setAttribute('sync-j', '%d' % d.sync_j)
     if d.sync_c:
@@ -1462,8 +1462,8 @@ https://gerrit.googlesource.com/git-repo/+/HEAD/docs/manifest-format.md
     d.destBranchExpr = node.getAttribute('dest-branch') or None
     d.upstreamExpr = node.getAttribute('upstream') or None
 
-    d.sync_j = XmlInt(node, 'sync-j', 1)
-    if d.sync_j <= 0:
+    d.sync_j = XmlInt(node, 'sync-j', None)
+    if d.sync_j is not None and d.sync_j <= 0:
       raise ManifestParseError('%s: sync-j must be greater than 0, not "%s"' %
                                (self.manifestFile, d.sync_j))