29 lines
4.5 KiB
Plaintext
29 lines
4.5 KiB
Plaintext
:sig
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DValue request_perf()
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:params
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return value : performance snapshot for the active request/workspace
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:see
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>sys
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>time_precise
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:content
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Returns a DValue with timing and process metadata such as worker pid, parent pid, request count, request start times, native dispatch, workspace setup and birth, context application, guest execution, and hostcall timing. `accept_us` is divided into `transport_params_us` (FastCGI begin through the end of parameters), `transport_input_us` (parameters through the end of input), and `handler_queue_us` (input close through handler entry). This distinguishes upstream request delivery from work inside the UCE handler.
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Hostcall totals include component resolution; `hostcall_cpu_us` separates thread CPU from hostcall wall time, and each bounded `hostcall_operations` item includes the same `cpu_us` attribution. `WASM_PROFILE_HOSTCALL_CPU=0` disables those per-hostcall thread-CPU samples and leaves their counters at zero when profiling cost matters more than that split. MySQL, memcache, and component resolution also expose their own count and microsecond fields. Workspace setup, birth, and context application expose matching wall and thread-CPU microseconds. `execution_cpu_us` is the remaining workspace thread CPU through the snapshot after those three phases. `unit_module_operations` is a source-root-relative list of up to 32 unit loads. Each item attributes module lookup/read/parse/build/classification plus allocation, import construction, symbol resolution, instantiation, and initialization; no caller-supplied paths are exposed. `mysql_operations` is an ordered, query-text-free list of up to 64 logical MySQL operations and their microsecond durations. A connect operation also identifies its source as `new`, cross-request `worker`, or same-request `request`; the corresponding `mysql_connection_open_count`, `mysql_connection_reuse_count`, and `mysql_request_pool_hit_count` fields provide totals. `mysql_operations_dropped` reports any overflow. The profiling hostcall itself is excluded from those totals so repeated snapshots remain comparable.
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Component resolution is divided into `component_path_us`, `component_artifact_us`, `component_load_us`, and `component_link_us`. These aggregate path resolution, artifact readiness/freshness, Wasmtime side-module loading, and exported-handler lookup/table placement without exposing source paths.
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Successful first loads within the request are counted by `unit_load_count` and divided into `unit_module_us`, `unit_allocate_us`, `unit_import_us`, `unit_instantiate_us`, and `unit_initialize_us`. These cover compiled-module lookup, guest memory/table allocation, import construction, Wasmtime instantiation, and relocations/constructors/request binding. Repeated handlers from an already loaded unit are excluded.
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`unit_module_cache_hit_count` and `unit_module_cache_miss_count` divide module loads by the worker's compiled-module cache. A miss is further identified by `unit_module_serialized_cache_hit_count` when Wasmtime deserializes the current `.cwasm`; `unit_module_compile_count` means it fell back to compiling the `.wasm`. `unit_module_lookup_us`, `unit_module_read_us`, `unit_module_read_bytes`, `unit_module_parse_us`, `unit_module_compile_us`, and `unit_module_classify_us` divide `unit_module_us` into artifact stat/cache lookup, wasm metadata/full-artifact read volume, custom-section parse, deserialize-or-compile, and immutable import classification. A current serialized-module hit scans only section headers and the `dylink.0`/`uce.abi` payloads; compilation fallback reads the complete wasm. The phase sum can be below the total because allocation and cache publication overhead remain in the aggregate.
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`unit_symbol_resolve_count` and `unit_symbol_resolve_us` isolate function and data symbol lookup within `unit_import_us`. The remainder of import time covers import-vector construction, Wasmtime Globals, GOT function table placement, and related bindings.
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Wasm FastCGI workers retain up to `MYSQL_PERSISTENT_POOL_SIZE` credential-keyed MySQL connections (default `8`; set `0` to disable). UCE calls the client library's connection-reset operation before another request receives a cached connection, clearing transactions, temporary tables, session variables, and selected databases while avoiding a new authentication handshake. Same-request leases continue to share state until request cleanup.
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:example
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DValue perf = request_perf();
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print(perf.get_type_name() != "invalid" ? "captured a timing snapshot" : "no data", "\n");
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