/// <summary>
/// Check if pip graph can be reused.
///
/// There are 3 opportunities to determine a graph match. The applicability of each depends on the distributed build roles.
/// (1) from engine cache,
/// (2) from content cache, and
/// (3) from master node (if running on a worker node in a distributed build)
/// </summary>
private GraphCacheCheckStatistics CheckGraphCacheReuse(
LoggingContext outerLoggingContext,
int maxDegreeOfParallelism,
GraphFingerprint graphFingerprint,
IReadOnlyDictionary <string, string> properties,
CacheInitializationTask cacheInitializationTask,
JournalState journalState,
out EngineSerializer serializer,
out InputTracker.InputChanges inputChanges)
{
serializer = CreateEngineSerializer(outerLoggingContext);
inputChanges = null;
var cacheGraphStats = default(GraphCacheCheckStatistics);
using (var timeBlock = TimedBlock <EmptyStruct, GraphCacheCheckStatistics> .Start(
outerLoggingContext,
Statistics.GraphCacheReuseCheck,
(context, emptyStruct) => Logger.Log.CheckingForPipGraphReuseStart(context),
default(EmptyStruct),
(loggingContext, stats) =>
{
Logger.Log.CheckingForPipGraphReuseComplete(loggingContext, stats);
// On misses we want to give the user a message for why there was a miss
if (!stats.WasHit)
{
Contract.Assume(stats.MissReason != GraphCacheMissReason.NoMiss);
Logger.Log.GraphNotReusedDueToChangedInput(loggingContext, stats.MissMessageForConsole, stats.MissDescription);
}
m_enginePerformanceInfo.GraphCacheCheckDurationMs = stats.ElapsedMilliseconds;
m_enginePerformanceInfo.GraphCacheCheckJournalEnabled = stats.JournalEnabled;
},
() => cacheGraphStats))
{
var loggingContext = timeBlock.LoggingContext;
var effectiveEnvironmentVariables = FrontEndEngineImplementation.PopulateFromEnvironmentAndApplyOverrides(properties);
var availableMounts = MountsTable.CreateAndRegister(loggingContext, Context, Configuration, m_initialCommandLineConfiguration.Startup.Properties);
if (!AddConfigurationMountsAndCompleteInitialization(loggingContext, availableMounts))
{
return(cacheGraphStats);
}
cacheGraphStats.JournalEnabled = journalState.IsEnabled;
// ************************************************************
// 1. Engine cache check:
// ************************************************************
// * Single machine builds
// Distributed builds rely on the graph being available via the cache for it to be shared between master
// and workers. So even if the master could have had a hit from the engine cache, it must be ignored
// since the workers would not be able to retrieve it.
if (!HasExplicitlyLoadedGraph(Configuration.Cache) &&
!Configuration.Schedule.ForceUseEngineInfoFromCache &&
Configuration.Distribution.BuildRole == DistributedBuildRoles.None)
{
Contract.Assume(
graphFingerprint != null,
"When looking up a cached graph on a distributed master or single-machine build, a graph fingerprint must be computed");
InputTracker.MatchResult engineCacheMatchResult = CheckIfAvailableInputsToGraphMatchPreviousRun(
loggingContext,
serializer,
graphFingerprint: graphFingerprint,
availableEnvironmentVariables: effectiveEnvironmentVariables,
availableMounts: availableMounts,
journalState: journalState,
maxDegreeOfParallelism: maxDegreeOfParallelism);
cacheGraphStats.ObjectDirectoryHit = engineCacheMatchResult.Matches;
cacheGraphStats.ObjectDirectoryMissReason = engineCacheMatchResult.MissType;
cacheGraphStats.MissReason = engineCacheMatchResult.MissType;
cacheGraphStats.MissDescription = engineCacheMatchResult.FirstMissIdentifier;
cacheGraphStats.WasHit = engineCacheMatchResult.Matches;
cacheGraphStats.InputFilesChecked = engineCacheMatchResult.FilesChecked;
// Checking the engine cache may have used a FileChangeTracker and provided information about
// files/ContentHash pairs that were unchanged from the previous run. Hold onto this information as it may
// be useful when eventually parsing files.
// The FileChangeTracker is now up to date. All changed files have been removed from it. It can be reused
// for a future build with the same fingerprint, though it may be tracking extra files, for example if
// a spec was removed since the previous build.
inputChanges = engineCacheMatchResult.InputChanges;
}
var shouldTryContentCache =
!cacheGraphStats.WasHit &&
Configuration.Distribution.BuildRole != DistributedBuildRoles.Worker &&
Configuration.Cache.AllowFetchingCachedGraphFromContentCache &&
!HasExplicitlyLoadedGraph(Configuration.Cache) &&
(!Configuration.FrontEnd.UseSpecPublicFacadeAndAstWhenAvailable.HasValue ||
!Configuration.FrontEnd.UseSpecPublicFacadeAndAstWhenAvailable.Value);
// ************************************************************
// 2. Content cache check:
// ************************************************************
// * Single machine builds that missed earlier
// * Distributed masters
// This is the only valid place for the master to get a hit since it must be in the cache for the
// workers to get it.
if (shouldTryContentCache)
{
// Since an in-place match did not succeed, we need a readied cache to try again.
// TODO: This logs an error if it fails. We are assuming some later thing will ensure that, if failed,
// the engine fails overall.
Possible <CacheInitializer> possibleCacheInitializerForFallback = cacheInitializationTask.GetAwaiter().GetResult();
if (possibleCacheInitializerForFallback.Succeeded)
{
CacheInitializer cacheInitializerForFallback = possibleCacheInitializerForFallback.Result;
using (EngineCache cacheForFallback = cacheInitializerForFallback.CreateCacheForContext())
{
var cacheGraphProvider = new CachedGraphProvider(
loggingContext,
Context,
cacheForFallback,
FileContentTable,
maxDegreeOfParallelism);
var cachedGraphDescriptor =
cacheGraphProvider.TryGetPipGraphCacheDescriptorAsync(graphFingerprint, effectiveEnvironmentVariables, availableMounts.MountsByName).Result;
if (cachedGraphDescriptor == null)
{
// There was no matching fingerprint in the cache. Record the status for logging before returning.
cacheGraphStats.CacheMissReason = GraphCacheMissReason.FingerprintChanged;
SetMissReasonIfUnset(ref cacheGraphStats, cacheGraphStats.CacheMissReason);
return(cacheGraphStats);
}
var fetchEngineScheduleContent = EngineSchedule.TryFetchFromCacheAsync(
loggingContext,
Context,
cacheForFallback,
cachedGraphDescriptor,
serializer,
FileContentTable,
m_tempCleaner).Result;
if (!fetchEngineScheduleContent)
{
cacheGraphStats.CacheMissReason = GraphCacheMissReason.NoPreviousRunToCheck;
SetMissReasonIfUnset(ref cacheGraphStats, cacheGraphStats.CacheMissReason);
return(cacheGraphStats);
}
// If a distributed master, take note of the graph fingerprint
if (Configuration.Distribution.BuildRole == DistributedBuildRoles.Master)
{
Contract.Assert(cachedGraphDescriptor != null);
m_masterService.CachedGraphDescriptor = cachedGraphDescriptor;
}
Logger.Log.FetchedSerializedGraphFromCache(outerLoggingContext);
cacheGraphStats.CacheMissReason = GraphCacheMissReason.NoMiss;
cacheGraphStats.MissReason = cacheGraphStats.CacheMissReason;
cacheGraphStats.WasHit = true;
}
}
else
{
cacheGraphStats.CacheMissReason = GraphCacheMissReason.CacheFailure;
SetMissReasonIfUnset(ref cacheGraphStats, cacheGraphStats.CacheMissReason);
return(cacheGraphStats);
}
}
// ************************************************************
// 3. Query distributed master
// ************************************************************
// * Distributed workers only
if (Configuration.Distribution.BuildRole == DistributedBuildRoles.Worker)
{
Contract.Assume(
graphFingerprint == null,
"Distributed workers should request a graph fingerprint from the master (not compute one locally)");
Possible <CacheInitializer> possibleCacheInitializerForWorker = cacheInitializationTask.GetAwaiter().GetResult();
Contract.Assume(possibleCacheInitializerForWorker.Succeeded, "Workers must have a valid cache");
CacheInitializer cacheInitializerForWorker = possibleCacheInitializerForWorker.Result;
using (EngineCache cacheForWorker = cacheInitializerForWorker.CreateCacheForContext())
{
PipGraphCacheDescriptor schedulerStateDescriptor;
if (!m_workerService.TryGetBuildScheduleDescriptor(out schedulerStateDescriptor) ||
!EngineSchedule.TryFetchFromCacheAsync(
outerLoggingContext,
Context,
cacheForWorker,
schedulerStateDescriptor,
serializer,
FileContentTable,
m_tempCleaner).Result)
{
cacheGraphStats.CacheMissReason = GraphCacheMissReason.NoFingerprintFromMaster;
cacheGraphStats.MissReason = cacheGraphStats.CacheMissReason;
return(cacheGraphStats);
}
AsyncOut <AbsolutePath> symlinkFileLocation = new AsyncOut <AbsolutePath>();
if (!SymlinkDefinitionFileProvider.TryFetchWorkerSymlinkFileAsync(
outerLoggingContext,
Context.PathTable,
cacheForWorker,
Configuration.Layout,
m_workerService,
symlinkFileLocation).Result)
{
cacheGraphStats.CacheMissReason = GraphCacheMissReason.NoFingerprintFromMaster;
cacheGraphStats.MissReason = cacheGraphStats.CacheMissReason;
return(cacheGraphStats);
}
m_workerSymlinkDefinitionFile = symlinkFileLocation.Value;
// Success. Populate the stats
cacheGraphStats.WasHit = true;
cacheGraphStats.WorkerHit = true;
cacheGraphStats.MissReason = GraphCacheMissReason.NoMiss;
cacheGraphStats.CacheMissReason = GraphCacheMissReason.NoMiss;
}
}
}
return(cacheGraphStats);
}
