Add mock_services standalone Thrift server (20 methods, real fbthrift) (#719) by excelle08 · Pull Request #719 · facebookresearch/DCPerf

excelle08 · 2026-07-02T18:31:13Z

Summary:

Phase 5 of the FeedSim v2 refactor needs LeafNodeRank to issue real outbound RPCs against a separate Thrift server so Strobelight categorizes the resulting CPU samples into the same rpc-stack/serialization/transport buckets as production multifeed_aggregator. This diff adds the mock_services binary that stands in for the 20 outbound RPC types observed in the production profile.

The server is built on real apache::thrift::ThriftServer, not the FeedSimServer hand-rolled AsyncServerSocket loop, so loopback dispatch goes through Cpp2Worker, RocketServerConnection, RequestRpcMetadata, CompactProtocolWriter, etc. exactly as it would in prod. The 20 thrift methods all share the same wire signature binary <method>(1: binary request, 2: i32 latency_us) (the design from phase5_researcher_notes section 1, option (c)) and dispatch to a single shared handler body. Distinct method names exist purely so Strobelight per-method attribution lines up with prod.

Wire contract: caller writes a uint32 big-endian response_size in the first 4 bytes of request and then opaque padding sized to the request percentile. The server sleeps/spins for latency_us and replies with response_size bytes copied from the Silesia corpus. Short-tail latencies (<200us) burn the IO thread to keep rpc-stack samples on-CPU; longer latencies hop to the global timekeeper.

Files added: MockService.thrift (IDL, 20 methods), MockServiceHandler.{h,cc} (single shared runSimulatedRpc body, 20 trivial wrappers behind a macro), MockServiceMain.cc (folly::Init + ThriftServer setup), BUCK (thrift_library + cpp_binary, with a -I flag pulling SilesiaLoader.h from the parent ranking/ dir since that dir has no BUCK file), CMakeLists.txt (open-source build path; mirrors the parent ranking/ pattern). Parent ranking/CMakeLists.txt picks up the new dir via add_subdirectory. The binary ships in the cea.chips.benchpress fbpkg automatically via the existing buck_filegroup glob over packages/feedsim/**.

Programmer B (sibling diff in this stack) wires LeafNodeRank's MockServiceAsyncClient and the issueOutboundFanout switch; Programmer C migrates compression to ManagedCompression. No file conflicts with this diff.

Reviewed By: charles-typ

Differential Revision: D103766817

meta-codesync · 2026-07-02T18:31:42Z

@excelle08 has exported this pull request. If you are a Meta employee, you can view the originating Diff in D103766817.

facebookresearch#719) Summary: Pull Request resolved: facebookresearch#719 Phase 5 of the FeedSim v2 refactor needs LeafNodeRank to issue real outbound RPCs against a separate Thrift server so Strobelight categorizes the resulting CPU samples into the same rpc-stack/serialization/transport buckets as production multifeed_aggregator. This diff adds the mock_services binary that stands in for the 20 outbound RPC types observed in the production profile. The server is built on real apache::thrift::ThriftServer, not the FeedSimServer hand-rolled AsyncServerSocket loop, so loopback dispatch goes through Cpp2Worker, RocketServerConnection, RequestRpcMetadata, CompactProtocolWriter, etc. exactly as it would in prod. The 20 thrift methods all share the same wire signature `binary <method>(1: binary request, 2: i32 latency_us)` (the design from phase5_researcher_notes section 1, option (c)) and dispatch to a single shared handler body. Distinct method names exist purely so Strobelight per-method attribution lines up with prod. Wire contract: caller writes a uint32 big-endian response_size in the first 4 bytes of `request` and then opaque padding sized to the request percentile. The server sleeps/spins for `latency_us` and replies with `response_size` bytes copied from the Silesia corpus. Short-tail latencies (<200us) burn the IO thread to keep rpc-stack samples on-CPU; longer latencies hop to the global timekeeper. Files added: MockService.thrift (IDL, 20 methods), MockServiceHandler.{h,cc} (single shared runSimulatedRpc body, 20 trivial wrappers behind a macro), MockServiceMain.cc (folly::Init + ThriftServer setup), BUCK (thrift_library + cpp_binary, with a -I flag pulling SilesiaLoader.h from the parent ranking/ dir since that dir has no BUCK file), CMakeLists.txt (open-source build path; mirrors the parent ranking/ pattern). Parent ranking/CMakeLists.txt picks up the new dir via add_subdirectory. The binary ships in the cea.chips.benchpress fbpkg automatically via the existing buck_filegroup glob over packages/feedsim/**. Programmer B (sibling diff in this stack) wires LeafNodeRank's MockServiceAsyncClient and the issueOutboundFanout switch; Programmer C migrates compression to ManagedCompression. No file conflicts with this diff. Reviewed By: charles-typ Differential Revision: D103766817

Summary: Add mock feature extraction pipeline to FeedSim with large-scale code generation for I-cache and frontend pressure. 27 genuinely diverse code patterns (derived from studying 696 production feature extractors) generate ~700 variants × 1000 copies = ~700K unique functions at install time. Key components: - 6 hand-written extractors based on production leaf function profiling - 27 pattern-specific code generators (P01-P27) producing genuinely different instruction sequences (different branch topologies, loop nesting, data access patterns, code sizes from 10 to 2300 lines) - Flat shuffled dispatch: all copy function pointers shuffled into one vector, iterated sequentially per request for maximum I-cache pressure - DLRM medium/large model generation on-server during install - Configurable via --num_stories, --extractors_per_story, --feature_complexity Results on T1_BGM (Bergamo, 176 cores): 500K calls/req: L1 I-Cache MPKI 21.34 (prod target 21), IPC 0.69 (prod 0.6-0.8) 100K calls/req: Frontend Bound 23.5%, IPC 1.22, QPS 242 Results on T11_GRC_ARM (Grace, 72 cores): 100K calls/req: IPC 0.52, L1 I-Cache MPKI 15.91 Medium DLRM + 100K calls: IPC 1.03 (prod target 1.05) Differential Revision: D97022149

Summary: Replace scalar FP transforms with integer hash operations, add data-dependent conditional branches, eliminate FP division with integer reciprocal approximation, deepen MockHashTable::find() call chain from 1 to 5 levels, and increase basic block sizes with MurmurHash-style computation chains. Results (5/7 instruction mix targets met on CPL): - Scalar FP: 8% → 0.46% (target <3.5%) ✓ - Conditional branches: 5.28% → 10.73% (target >15%) ✗ - Near call/return: 3.93% → 0.75% (target <1.5%) ✓ - Memory (ld+st): 51.56% → 40.72% (target 40-46%) ✓ - Divider active: 11.50% → 1.13% (target <2%) ✓ - Avg BB size: 7.3 → 13.7 (LBR, target >18) ✗ QPS impact: CPL -2.2%, BGM -6.3%, Grace -3.8%. Differential Revision: D99494831

Summary: Replace oldisim framework internals (libevent server, pthreads, boost::lockfree) with folly-based equivalents for LeafNodeRank and DriverNodeRank. ParentNodeRank retains oldisim dependency. New files: - FeedSimProtocol.h: Wire protocol types (binary compatible with oldisim) - FeedSimServer.{h,cc}: Server using folly::AsyncServerSocket + folly::EventBase - FeedSimDriver.{h,cc}: Client driver with libevent for timer precision Modified: - LeafNodeRank.cc: Use feedsim::FeedSimServer, feedsim::RequestContext - DriverNodeRank.cc: Use feedsim::FeedSimDriver, feedsim::TestDriver - CMakeLists.txt: Add FeedSimFramework library, replace OLDISim link dep - utils.h: Remove oldisim DIE() dependency - run.sh: Change readiness check from HTTP monitor port to TCP data port Differential Revision: D99498073

Summary: Phase 3 of FeedSim v2 refactor. Client loads the Silesia compression corpus (203MB, 12 files) via mmap, picks random snippets as "stories," and sends them to the server via thrift. Server uses story content to derive data-dependent feature extraction inputs and DLRM features instead of random data. Changes: - Add StoryContent/StoryBatch thrift types and story_batch field on RankingRequest - Add SilesiaLoader.h: mmap-based corpus loader with random snippet serving - Update DriverNodeRank to load Silesia at startup, populate stories per request - Update LeafNodeRank to extract stories, derive features from content bytes (byte frequency histogram -> dense features, rolling bigram hash -> sparse) - Rewrite DLRMRequestHandler from sync to async with folly futures (I/O simulation + compression + pointer chase, pipelined) - Add storyContent/storyContentLength fields to CopyContext for extractors - Fix feature_suite missing from ThreadData (lost during rebase) - Fix $feature_opts not passed to LeafNodeRank in run.sh - Fix runFeatureExtraction() never called from request handlers - Fix ICacheBuster SIGSEGV: init moved outside PAGERANK block - Remove ICacheBuster from DLRMRequestHandler (DLRM inference is own workload) - Add --silesia-dir, --stories-per-request, --story-size-min/max CLI options - Download Silesia corpus during install (x86 + aarch64) Differential Revision: D104076734

Summary: FeedSim's profile shows RPC at 4-5% vs production's 30-34% — partly because the benchmark sends tiny requests with no resemblance to production's payload size distribution. This diff lets the client sample a target serialized request size from a JSON percentile distribution and pad the request to hit that size. Changes: - Add `optional binary padding` field to `RankingRequest` thrift struct - New `RequestSizeSampler` (header-only) loads a JSON file of percentile data (`req_size_min`, `req_size_p05`, ... `req_size_max`) and samples target sizes via inverse-CDF with linear interpolation between percentiles - Add `--req_size_dist <json>` flag to DriverNodeRank. When present, each request is built normally, then padded with Silesia bytes (or random bytes if Silesia not loaded) to reach the sampled target size - Plumb `--req-size-dist` through `run.sh` with auto-detection of `feed_aggregator_req_sizes.json` next to `run.sh` - Bundle `feed_aggregator_req_sizes.json` and `feed_aggregator_resp_sizes.json` (production data from ServiceRouter) and copy them in install scripts Differential Revision: D102693799

…onse generator Summary: Several cleanups in LeafNodeRank, all motivated by the leaf-only hot-func breakdown which surfaced ~15% of CPU on server-side response RNG and the misleading-named dlrmInferenceServerSideDataGeneration: 1. Split DLRM inference into two functions, both async (return folly::Future<int>): - dlrmInferenceServerSide: inference path where features are generated inside DLRM::infer (server-side) - dlrmInferenceClientSide: inference path that uses DLRM::inferWithFeatures with client-provided dense+sparse features The old name dlrmInferenceServerSideDataGeneration hid the actual ML inference call (this_thread.dlrm_ranker->infer) inside a function whose name suggested it was just generating feature data. The new names are honest. A shared shardInferences() helper distributes work across cpu_threads_arg. 2. Rewrite DLRMRequestHandler to be fully async with a single future chain (DLRM inference -> I/O sleep -> compression -> pointer chase -> generate+send response). The previous code blocked synchronously on the inference future via .get() before starting the rest of the pipeline. Now the handler thread returns immediately after kicking off the chain. 3. Pick the right inference function based on what the client sent: if request.dlrm_features() is set, use dlrmInferenceClientSide (no server RNG for inputs); otherwise dlrmInferenceServerSide. 4. Remove the dead `else if (g_workload_type == DLRM)` branches from PageRankRequestHandler and AsyncPageRankRequestHandler. DLRM workload requests use kDLRMRequestType, which routes to DLRMRequestHandler (registered separately in main()), so the DLRM branch in PageRank handlers was unreachable. 5. New Silesia-backed server response generator (generators/SilesiaResponseGenerator.h). When the server is started with --silesia_dir, response RankingObjects/RankingStorys are populated by slicing bytes out of the mmap'd Silesia corpus instead of running xor128() RNG. Replaces ~15% of leaf CPU previously spent on RNG (mersenne_twister, generateRandomString, xor128) with cheap memcpy from a hot mmap. The bytes have realistic entropy for downstream ZSTD compression. 6. Added LeafNodeRank --silesia_dir option and plumbed through run.sh. The same --silesia-dir flag now provides bytes both to DriverNodeRank's story_batch and to the server's response generator. Differential Revision: D103100125

…KER, GlobalCPUThread Summary: LeafNodeRank's existing thread pools were anonymous from Strobelight's point of view, so the prod-vs-bench thread-pool breakdown landed almost entirely in the `Unknown` / framework-noise bucket on CPL and BGM. Per the multifeed_aggregator prod profile (~/feedsim_v2/profiles/multifeed_aggregator_main_prod/), the four hot pools are `ThriftSrv.IO`, `SREventBase{N}`, `RANKER-{N}`, and `GlobalCPUThread` (see ~/feedsim_v2/docs/phase4_researcher_notes.md section 1). This diff is the Programmer-A half of Phase 4 (thread pools only). It renames the four existing pools to match the prod names that Strobelight categorizes, and adds two new pools (`SREventBase`, `RANKER`) that Phase 5 will start dispatching outbound RPC fanout onto. Programmer-B's diff (thrift schema + 5 new method registrations) lands as a sibling commit; via() callsites stay on their existing pool aliases so this rename is a no-op behaviorally. Changes: - `cpuThreadPool` is now backed by `folly::getGlobalCPUExecutor()` (the folly singleton already exposes its threads as `GlobalCPUThread` via `NamedThreadFactory("GlobalCPUThreadPool")` in `folly/executors/GlobalExecutor.cpp:65`). DO NOT instantiate a second CPU pool — that would double-count the prod `GlobalCPUThread` category. The `ThreadData::cpuThreadPool` field type changed from `shared_ptr<CPUThreadPoolExecutor>` to `shared_ptr<folly::Executor>` so the same field can hold the global singleton via an aliasing shared_ptr that owns a `folly::Executor::KeepAlive<>`. All existing `folly::via(this_thread.cpuThreadPool.get(), ...)` callsites continue to compile because `folly::via` accepts an `Executor*`. - `srvCPUThreadPool` is now `NamedThreadFactory("RANKER")`, sized `max(1, nproc/2)` by default (matches CPL prod: 26 RANKER threads on a 52-logical-core host). Tunable via the new `--ranker_threads` flag. - `ioThreadPool` is now `NamedThreadFactory("ThriftSrv.IO")`, sized `--io_threads`. Was previously anonymous (the kernel just labeled the threads with the executable name). - New `srEventBasePool` (`folly::IOThreadPoolExecutor`, `NamedThreadFactory("SREventBase")`), sized `max(1, nproc * 7 / 10)` (matches CPL prod: 39 SREventBase threads on a 52-logical-core host). Tunable via the new `--sr_event_base_threads` flag. Idle in Phase 4 — Phase 5 wires the outbound mock_services fanout onto it. Threads are warmed up at server start so Strobelight sees them in steady state. - The legacy `srvIOThreadPool` (compression dispatch) is preserved for now and retired in Phase 6 once compression callsites move onto `GlobalCPUThread` per the researcher notes. - New CLI flags `--ranker_threads` and `--sr_event_base_threads` in `LeafNodeRankCmdline.ggo`. Default `0` means "auto-compute from `folly::available_concurrency()` per the formulas above". - Includes added: `<folly/executors/GlobalExecutor.h>` and `<folly/system/HardwareConcurrency.h>`. Both are already on `${FOLLY_INCLUDE_DIR}` in the existing CMake target so no `CMakeLists.txt` edits were required. Differential Revision: D103766488

facebookresearch#719) Summary: Pull Request resolved: facebookresearch#719 Phase 5 of the FeedSim v2 refactor needs LeafNodeRank to issue real outbound RPCs against a separate Thrift server so Strobelight categorizes the resulting CPU samples into the same rpc-stack/serialization/transport buckets as production multifeed_aggregator. This diff adds the mock_services binary that stands in for the 20 outbound RPC types observed in the production profile. The server is built on real apache::thrift::ThriftServer, not the FeedSimServer hand-rolled AsyncServerSocket loop, so loopback dispatch goes through Cpp2Worker, RocketServerConnection, RequestRpcMetadata, CompactProtocolWriter, etc. exactly as it would in prod. The 20 thrift methods all share the same wire signature `binary <method>(1: binary request, 2: i32 latency_us)` (the design from phase5_researcher_notes section 1, option (c)) and dispatch to a single shared handler body. Distinct method names exist purely so Strobelight per-method attribution lines up with prod. Wire contract: caller writes a uint32 big-endian response_size in the first 4 bytes of `request` and then opaque padding sized to the request percentile. The server sleeps/spins for `latency_us` and replies with `response_size` bytes copied from the Silesia corpus. Short-tail latencies (<200us) burn the IO thread to keep rpc-stack samples on-CPU; longer latencies hop to the global timekeeper. Files added: MockService.thrift (IDL, 20 methods), MockServiceHandler.{h,cc} (single shared runSimulatedRpc body, 20 trivial wrappers behind a macro), MockServiceMain.cc (folly::Init + ThriftServer setup), BUCK (thrift_library + cpp_binary, with a -I flag pulling SilesiaLoader.h from the parent ranking/ dir since that dir has no BUCK file), CMakeLists.txt (open-source build path; mirrors the parent ranking/ pattern). Parent ranking/CMakeLists.txt picks up the new dir via add_subdirectory. The binary ships in the cea.chips.benchpress fbpkg automatically via the existing buck_filegroup glob over packages/feedsim/**. Programmer B (sibling diff in this stack) wires LeafNodeRank's MockServiceAsyncClient and the issueOutboundFanout switch; Programmer C migrates compression to ManagedCompression. No file conflicts with this diff. Reviewed By: charles-typ Differential Revision: D103766817

#719) Summary: Pull Request resolved: #719 Phase 5 of the FeedSim v2 refactor needs LeafNodeRank to issue real outbound RPCs against a separate Thrift server so Strobelight categorizes the resulting CPU samples into the same rpc-stack/serialization/transport buckets as production multifeed_aggregator. This diff adds the mock_services binary that stands in for the 20 outbound RPC types observed in the production profile. The server is built on real apache::thrift::ThriftServer, not the FeedSimServer hand-rolled AsyncServerSocket loop, so loopback dispatch goes through Cpp2Worker, RocketServerConnection, RequestRpcMetadata, CompactProtocolWriter, etc. exactly as it would in prod. The 20 thrift methods all share the same wire signature `binary <method>(1: binary request, 2: i32 latency_us)` (the design from phase5_researcher_notes section 1, option (c)) and dispatch to a single shared handler body. Distinct method names exist purely so Strobelight per-method attribution lines up with prod. Wire contract: caller writes a uint32 big-endian response_size in the first 4 bytes of `request` and then opaque padding sized to the request percentile. The server sleeps/spins for `latency_us` and replies with `response_size` bytes copied from the Silesia corpus. Short-tail latencies (<200us) burn the IO thread to keep rpc-stack samples on-CPU; longer latencies hop to the global timekeeper. Files added: MockService.thrift (IDL, 20 methods), MockServiceHandler.{h,cc} (single shared runSimulatedRpc body, 20 trivial wrappers behind a macro), MockServiceMain.cc (folly::Init + ThriftServer setup), BUCK (thrift_library + cpp_binary, with a -I flag pulling SilesiaLoader.h from the parent ranking/ dir since that dir has no BUCK file), CMakeLists.txt (open-source build path; mirrors the parent ranking/ pattern). Parent ranking/CMakeLists.txt picks up the new dir via add_subdirectory. The binary ships in the cea.chips.benchpress fbpkg automatically via the existing buck_filegroup glob over packages/feedsim/**. Programmer B (sibling diff in this stack) wires LeafNodeRank's MockServiceAsyncClient and the issueOutboundFanout switch; Programmer C migrates compression to ManagedCompression. No file conflicts with this diff. Reviewed By: charles-typ Differential Revision: D103766817 fbshipit-source-id: fba9ef86fabdb157d9c7a2c81e8c9f2be85675bf

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meta-codesync Bot changed the title ~~Add mock_services standalone Thrift server (20 methods, real fbthrift)~~ Add mock_services standalone Thrift server (20 methods, real fbthrift) (#719) Jul 2, 2026

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Add mock_services standalone Thrift server (20 methods, real fbthrift) (#719) - #719

Add mock_services standalone Thrift server (20 methods, real fbthrift) (#719)#719
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