public async Task TestGcPrefix()
{
string cacheConfig = TestType.NewCache(nameof(TestGcPrefix), true);
BasicFilesystemCache cache = (await InitializeCacheAsync(cacheConfig).SuccessAsync()) as BasicFilesystemCache;
XAssert.IsNotNull(cache, "Failed to create cache for GC tests!");
PipDefinition[] pips =
{
new PipDefinition("Pip1", pipSize: 3),
new PipDefinition("Pip2", pipSize: 4),
new PipDefinition("Pip3", pipSize: 5)
};
// First, lets filter the GC to only do one of the files.
CacheEntries files = await BuildPipsAndGetCacheEntries(cache, "Build", pips);
cache.DeleteSession("Build");
for (int i = 1; i < 4; i++)
{
files.AgeAll();
string targetFile = files.FingerprintFiles.Keys.First();
// Get the shard directory of the weak fingerprint
string prefix = Path.GetFileName(Path.GetDirectoryName(Path.GetDirectoryName(targetFile)));
XAssert.AreEqual(3, prefix.Length);
m_output.WriteLine("GC Prefix: [{0}]", prefix);
var stats = cache.CollectUnreferencedFingerprints(m_output, prefixFilter: prefix.Substring(0, i));
XAssert.IsFalse(File.Exists(targetFile), "Should have moved this one to pending");
BasicFilesystemCache.UndoPendingDelete(targetFile);
files.AssertExists();
}
AssertSuccess(await cache.ShutdownAsync());
}
public async Task TestGcConcurrency()
{
// This is just minimal concurrency testing such that it does not completely mess up
// Most of the work in making the GC safe was in the design and hand testing as this
// is about having a GC run while multiple mutators run (and multiple GCs run)
string cacheConfig = TestType.NewCache(nameof(TestGcConcurrency), true);
BasicFilesystemCache cache = (await InitializeCacheAsync(cacheConfig).SuccessAsync()) as BasicFilesystemCache;
XAssert.IsNotNull(cache, "Failed to create cache for GC tests!");
PipDefinition[] pips =
{
new PipDefinition("Pip1", pipSize: 3),
new PipDefinition("Pip2", pipSize: 4),
new PipDefinition("Pip3", pipSize: 5),
new PipDefinition("Pip4", pipSize: 4),
new PipDefinition("Pip5", pipSize: 3)
};
CacheEntries files = await BuildPipsAndGetCacheEntries(cache, "Build", pips);
// First have the GC do nothing (all items still rooted but old enough to collect)
files.AgeAll();
ParallelConcurrentFullGc(cache, "Noop");
files.AssertExists();
// Now delete the session and make sure we collect correctly
cache.DeleteSession("Build");
// This may take a few tries to get all of the items GC'ed
// Since we assume that the GC will always work, any error returned
// by the GC will trigger a fault and failure of the test.
// However, the GC is designed to, if anything is in question at
// all, to just skip deleting (or marking as pending delete)
// any item that is busy or otherwise engaged. This does mean that
// multiple concurrent GC can, in rare cases, cause a file
// (specifically a strong fingerprint) to not get collected for
// a given pass due to the file being in use by another GC.
// This is perfectly correct and will cause that item to be
// collected later. However, later may require another
// aging of the files since the file age may have been
// reset during the failed attempt to mark it pending.
// (Which is a good thing since failing to mark pending is
// a potential sign that something is using it and thus
// it is not yet ready to be changed)
// Anyway, the number of passes and the exact state of the GC
// is not directly knowable due to these races but they sure should
// not be greater than 100
int pass = 0;
while (files.Count > 0)
{
files.AgeAll();
pass++;
ParallelConcurrentFullGc(cache, "Pass #" + pass);
// Make sure some progress happened
// That means some items had to be marked pending or
// got collected each time through the process.
// This will make sure we are always making some
// progress with the GC and thus will terminate.
files.AssertMissingSome();
files = new CacheEntries(cache);
}
AssertSuccess(await cache.ShutdownAsync());
}
public async Task TestGcMultiSession()
{
string cacheConfig = TestType.NewCache(nameof(TestGcMultiSession), true);
BasicFilesystemCache cache = (await InitializeCacheAsync(cacheConfig).SuccessAsync()) as BasicFilesystemCache;
XAssert.IsNotNull(cache, "Failed to create cache for GC tests!");
// Verify that we don't have prior content in the cache
XAssert.AreEqual(0, new CacheEntries(cache).Count, "Test cache did not start out empty!");
// Also used for session 3
PipDefinition[] pipsSession1 =
{
new PipDefinition("Pip1", pipSize: 3),
new PipDefinition("Pip2", pipSize: 4),
new PipDefinition("Pip3", pipSize: 5)
};
// This should just bring back from the "pending" one pip with 4 outputs
// Also used for session 4
PipDefinition[] pipsSession2 =
{
new PipDefinition("Pip2", pipSize: 4)
};
CacheEntries session1Files = await BuildPipsAndGetCacheEntries(cache, "Session1", pipsSession1);
CacheEntries session2Files = await BuildPipsAndGetCacheEntries(cache, "Session2", pipsSession2);
// The second session should not have changed anything as the pip already existed
XAssert.IsFalse(session2Files.AreDifferences(session1Files), "We changed the cache when we should not have!");
// Nothing should change on this GC since the files are all referenced
session1Files.AgeAll();
FullGc(cache);
session1Files.AssertExists();
// Nothing should change because of session 2 deleting since the fingerprint still exists in session1
cache.DeleteSession("Session2");
FullGc(cache);
session1Files.AssertExists();
// Deleteing session 1 should cause all fingerprints to become pending delete
cache.DeleteSession("Session1");
FullGc(cache);
CacheEntries session1GcFpPending = new CacheEntries(cache);
XAssert.IsFalse(session1GcFpPending.FingerprintFiles.Keys.Any(IsNotPendingDelete), "All fingerprints should be pending delete");
XAssert.IsFalse(session1GcFpPending.CasFiles.Keys.Any(IsPendingDelete), "All cas should not be pending delete");
// Rebuilding the pips from session1a should restore the pending delete to non-pending delete (in fact, restore to session1Files)
CacheEntries session3Files = await BuildPipsAndGetCacheEntries(cache, "Session3", pipsSession1);
XAssert.IsFalse(session3Files.AreDifferences(session1Files), "Should be back to the same after rebuilding - no pending");
cache.DeleteSession("Session3");
session3Files.AgeAll();
FullGc(cache);
CacheEntries session3GcFpPending = new CacheEntries(cache);
XAssert.IsFalse(session3GcFpPending.FingerprintFiles.Keys.Any(IsNotPendingDelete), "All fingerprints should be pending delete");
XAssert.IsFalse(session3GcFpPending.CasFiles.Keys.Any(IsPendingDelete), "All cas should not be pending delete");
// Build the session2 single pip (as session 4) to recover the pending
CacheEntries session4Files = await BuildPipsAndGetCacheEntries(cache, "Session4", pipsSession2);
XAssert.AreEqual(session1Files.Count, session4Files.Count, "Should not have made any extra files");
XAssert.AreEqual(1, session4Files.FingerprintFiles.Keys.Count(IsNotPendingDelete), "Should have 1 non-pending delete fingerprint");
// This should collect all but the one fingerprint from session 4 and mark pending all of the cas entries
// except the 5 cas entries from session 4. (4 cas outputs plus the cas input list in the fingerprint)
session4Files.AgeAll();
FullGc(cache);
CacheEntries session4Gc = new CacheEntries(cache);
XAssert.AreEqual(1, session4Gc.FingerprintFiles.Count, "Should only have one fingerprint file left");
XAssert.AreEqual(session1Files.CasFiles.Count, session4Gc.CasFiles.Count);
XAssert.AreEqual(5, session4Gc.CasFiles.Keys.Count(IsNotPendingDelete), "Only Pip2 cas should be non-pending");
cache.DeleteSession("Session4");
// Pip2 fingerprint to pending
session4Gc.AgeAll();
FullGc(cache);
// Pip2 fingerprint from pending to delete - cas entries to pending
new CacheEntries(cache).AgeAll();
FullGc(cache);
CacheEntries session4GcCasPending = new CacheEntries(cache);
XAssert.AreEqual(0, session4GcCasPending.FingerprintFiles.Count, "All fingerprints should be gone");
XAssert.IsFalse(session4GcCasPending.CasFiles.Keys.Any(IsNotPendingDelete), "All cas should be pending delete");
// Pip2 cas entries from pending to delete
session4GcCasPending.AgeAll();
FullGc(cache);
XAssert.AreEqual(0, new CacheEntries(cache).Count, "All should be collected now");
AssertSuccess(await cache.ShutdownAsync());
}
public async Task TestGcMulti()
{
// To keep test time down, we do all of the "safely skipped during GC" tests in one go
// This is actually safe as I then validate that it recovers later. Under normal conditions
// this rarely happens but we want to make sure that the GC can handle the concurrent access
// characteristics and this hits those other code paths.
string cacheConfig = TestType.NewCache(nameof(TestGcMulti), true);
BasicFilesystemCache cache = (await InitializeCacheAsync(cacheConfig).SuccessAsync()) as BasicFilesystemCache;
XAssert.IsNotNull(cache, "Failed to create cache for GC tests!");
foreach (var build in DoBuilds(cache, 4).OutOfOrderTasks())
{
await build;
}
// Now delete the sessions one at a time and age at each step
for (int i = 0; i < 4; i++)
{
new CacheEntries(cache).AgeAll();
FullGc(cache);
cache.DeleteSession("Build" + i);
}
// At this point we should have deleted a few items at each level
// The last session should still have been alive at the last GC
// so we should now have both pending and non-pending in both the
// fingerprints and CAS
CacheEntries files = new CacheEntries(cache);
XAssert.IsTrue(files.FingerprintFiles.Keys.Any(IsPendingDelete));
XAssert.IsTrue(files.FingerprintFiles.Keys.Any(IsNotPendingDelete));
XAssert.IsTrue(files.CasFiles.Keys.Any(IsPendingDelete));
XAssert.IsTrue(files.CasFiles.Keys.Any(IsNotPendingDelete));
// Age them all
files.AgeAll();
// Now, we need to open some files of each time and run a GC to see that it works.
using (var notPendingFingerprint = files.FingerprintFiles.First(kv => IsNotPendingDelete(kv.Key)).Value.OpenRead())
{
using (var pendingFingerprint = files.FingerprintFiles.First(kv => IsPendingDelete(kv.Key)).Value.OpenRead())
{
using (var notPendingCas = files.CasFiles.First(kv => IsNotPendingDelete(kv.Key)).Value.OpenRead())
{
using (var pendingCas = files.CasFiles.First(kv => IsPendingDelete(kv.Key)).Value.OpenRead())
{
// This should allow the GC to continue but some things will not be collected
// to do failed deletes and failed renames to pending
var stats = FullGc(cache);
XAssert.AreEqual(1, stats["CAS_Skipped"], "Should have skipped a CAS entry");
XAssert.AreEqual(2, stats["Fingerprint_Skipped"], "Should have skipped 2 Fingerprints");
}
}
}
}
// Now with the files not blocked from delete/rename, run the GC again (no fresh aging)
var statsRemaining = FullGc(cache);
XAssert.AreEqual(1, statsRemaining["Fingerprint_Collected"], "Collected the one fingerprint that was held open");
XAssert.AreEqual(1, statsRemaining["Fingerprint_Pending"], "Moved to pending the one fingerprint that was held open");
XAssert.AreEqual(1, statsRemaining["CAS_Collected"], "Collected the one CAS item that was held open");
XAssert.AreEqual(4, statsRemaining["CAS_Pending"], "Moved to pending the one CAS item that was held open and the 3 CAS items that were referenced by the fingerprint that was held");
// Check that the partition counts match as needed
XAssert.AreEqual((TestType is TestBasicFilesystemSharded) ? TestBasicFilesystemSharded.SHARD_COUNT : 1, statsRemaining["Fingerprint_Partitions"]);
XAssert.AreEqual((TestType is TestBasicFilesystemSharded) ? TestBasicFilesystemSharded.SHARD_COUNT : 1, statsRemaining["CAS_Partitions"]);
AssertSuccess(await cache.ShutdownAsync());
}
public async Task TestGcBasic()
{
string cacheConfig = TestType.NewCache(nameof(TestGcBasic), true);
BasicFilesystemCache cache = (await InitializeCacheAsync(cacheConfig).SuccessAsync()) as BasicFilesystemCache;
XAssert.IsNotNull(cache, "Failed to create cache for GC tests!");
// Verify that we don't have prior content in the cache
XAssert.AreEqual(0, new CacheEntries(cache).Count, "Test cache did not start out empty!");
PipDefinition[] pipsSession1 =
{
new PipDefinition("Pip1", pipSize: 3),
new PipDefinition("Pip2", pipSize: 4),
new PipDefinition("Pip3", pipSize: 5)
};
CacheEntries session1Files = await BuildPipsAndGetCacheEntries(cache, "Session1", pipsSession1);
// Nothing should change on this GC since the files and are all referenced
FullGc(cache);
session1Files.AssertExists();
session1Files.AgeAll();
// Everything is rooted so nothing should happen here
FullGc(cache);
XAssert.IsFalse(new CacheEntries(cache).AreDifferences(session1Files), "We changed the cache when we should not have!");
// Now, if we delete the session, we should collect things.
cache.DeleteSession("Session1");
FullGc(cache);
// All of the fingerprints should be changed to pending but nothing should be deleted
CacheEntries session1gcFpPending = new CacheEntries(cache);
XAssert.AreEqual(session1Files.Count, session1gcFpPending.Count, "Nothing should have been added or deleted!");
XAssert.IsFalse(session1gcFpPending.FingerprintFiles.Keys.Any(IsNotPendingDelete), "All fingerprints should be pending delete");
XAssert.IsFalse(session1gcFpPending.CasFiles.Keys.Any(IsPendingDelete), "All cas should not be pending delete");
// Nothing to happen here as the pending files are too new
FullGc(cache);
// Nothing changed...
XAssert.IsFalse(new CacheEntries(cache).AreDifferences(session1gcFpPending), "We changed the cache when we should not have!");
// Now age the pending delete such that they are collected
session1gcFpPending.AgeAll();
FullGc(cache);
CacheEntries session1gcCas1 = new CacheEntries(cache);
XAssert.AreEqual(0, session1gcCas1.FingerprintFiles.Count, "Should have collected all fingerprints");
// And, we should have moved to pending all CAS items (since there is no pending)
XAssert.IsFalse(session1gcCas1.CasFiles.Keys.Any(IsNotPendingDelete), "All cas should be pending delete");
FullGc(cache); // Should do nothing as they are not old enough pending
XAssert.IsFalse(new CacheEntries(cache).AreDifferences(session1gcCas1), "We changed the cache when we should not have!");
// After getting all to be old, this should finally GC it all
session1gcCas1.AgeAll();
FullGc(cache);
XAssert.AreEqual(0, new CacheEntries(cache).Count, "Should have collected everything.");
AssertSuccess(await cache.ShutdownAsync());
}