Test uniform bitmap commit selection across multiple branches

Test that the commit selection algorithm provides appropriate
coverage across all branches.

Change-Id: I82c71b52068f01e8cef2398aecfec8e144d9a68b
Signed-off-by: Terry Parker <tparker@google.com>
This commit is contained in:
tparker 2018-06-22 16:10:11 -07:00 committed by Terry Parker
parent 82ae431e45
commit 34fb1d7d21
1 changed files with 101 additions and 6 deletions

View File

@ -50,6 +50,7 @@
import java.util.ArrayList;
import java.util.Arrays;
import java.util.Collections;
import java.util.HashSet;
import java.util.List;
import java.util.Set;
@ -243,7 +244,8 @@ public void testSelectionOrderingWithChains() throws Exception {
List<RevCommit> commits = Arrays.asList(m0, m1, m2, b3, m4, b5, m6, b7,
m8, m9);
PackWriterBitmapPreparer preparer = newPeparer(m9, commits);
PackWriterBitmapPreparer preparer = newPreparer(
Collections.singleton(m9), commits, new PackConfig());
List<BitmapCommit> selection = new ArrayList<>(
preparer.selectCommits(commits.size(), PackWriter.NONE));
@ -267,15 +269,108 @@ private RevCommit addCommit(BranchBuilder bb, String msg,
return commit.create();
}
private PackWriterBitmapPreparer newPeparer(RevCommit want,
List<RevCommit> commits)
throws IOException {
@Test
public void testDistributionOnMultipleBranches() throws Exception {
BranchBuilder[] branches = { tr.branch("refs/heads/main"),
tr.branch("refs/heads/a"), tr.branch("refs/heads/b"),
tr.branch("refs/heads/c") };
RevCommit[] tips = new RevCommit[branches.length];
List<RevCommit> commits = createHistory(branches, tips);
PackConfig config = new PackConfig();
config.setBitmapContiguousCommitCount(1);
config.setBitmapRecentCommitSpan(5);
config.setBitmapDistantCommitSpan(20);
config.setBitmapRecentCommitCount(100);
Set<RevCommit> wants = new HashSet<>(Arrays.asList(tips));
PackWriterBitmapPreparer preparer = newPreparer(wants, commits, config);
List<BitmapCommit> selection = new ArrayList<>(
preparer.selectCommits(commits.size(), PackWriter.NONE));
Set<ObjectId> selected = new HashSet<>();
for (BitmapCommit c : selection) {
selected.add(c.toObjectId());
}
// Verify that each branch has uniform bitmap selection coverage
for (RevCommit c : wants) {
assertTrue(selected.contains(c.toObjectId()));
int count = 1;
int selectedCount = 1;
RevCommit parent = c;
while (parent.getParentCount() != 0) {
parent = parent.getParent(0);
count++;
if (selected.contains(parent.toObjectId())) {
selectedCount++;
}
}
// The selection algorithm prefers merges and will look in the
// current range plus the recent commit span before selecting a
// commit. Since this history has no merges, we expect the recent
// span should have 100/10=10 and distant commit spans should have
// 100/25=4 per 100 commit range.
int expectedCount = 10 + (count - 100 - 24) / 25;
assertTrue(expectedCount <= selectedCount);
}
}
private List<RevCommit> createHistory(BranchBuilder[] branches,
RevCommit[] tips) throws Exception {
/*-
* Create a history like this, where branches a, b and c branch off of the main branch
* at commits 100, 200 and 300, and where commit times move forward alternating between
* branches.
*
* o...o...o...o...o commits root,m0,m1,...,m399
* \ \ \
* \ \ o... commits branch_c,c300,c301,...,c399
* \ \
* \ o...o... commits branch_b,b200,b201,...,b399
* \
* o...o...o... commits branch_a,b100,b101,...,a399
*/
List<RevCommit> commits = new ArrayList<>();
String[] prefixes = { "m", "a", "b", "c" };
int branchCount = branches.length;
tips[0] = addCommit(commits, branches[0], "root");
int counter = 0;
for (int b = 0; b < branchCount; b++) {
for (int i = 0; i < 100; i++, counter++) {
for (int j = 0; j <= b; j++) {
tips[j] = addCommit(commits, branches[j],
prefixes[j] + counter);
}
}
// Create a new branch from current value of the master branch
if (b < branchCount - 1) {
tips[b + 1] = addCommit(branches[b + 1],
"branch_" + prefixes[b + 1], tips[0]);
}
}
return commits;
}
private RevCommit addCommit(List<RevCommit> commits, BranchBuilder bb,
String msg, RevCommit... parents) throws Exception {
CommitBuilder commit = bb.commit().message(msg).add(msg, msg).tick(1);
if (parents.length > 0) {
commit.noParents();
for (RevCommit parent : parents) {
commit.parent(parent);
}
}
RevCommit c = commit.create();
tr.parseBody(c);
commits.add(c);
return c;
}
private PackWriterBitmapPreparer newPreparer(Set<RevCommit> wants,
List<RevCommit> commits, PackConfig config) throws IOException {
List<ObjectToPack> objects = new ArrayList<>(commits.size());
for (RevCommit commit : commits) {
objects.add(new ObjectToPack(commit, Constants.OBJ_COMMIT));
}
Set<ObjectId> wants = Collections.singleton((ObjectId) want);
PackConfig config = new PackConfig();
PackBitmapIndexBuilder builder = new PackBitmapIndexBuilder(objects);
return new PackWriterBitmapPreparer(
tr.getRepository().newObjectReader(), builder,