ydb/library/cpp/yt/system, branch CLI_2.32.0

Add TTscp::GetApproximate

2026-06-18T10:04:31Z

TTscp::GetApproximate takes the processor id from the rseq fast path (GetCurrentCpuId) and the instant from a non-serializing rdtsc, instead of the single serializing rdtscp of TTscp::Get. TPerCpuGauge::Update switches to it: the per-shard timestamp only orders writes across shards to pick the freshest value, so the lower precision is fine. Update is virtual and now YT_PREVENT_TLS_CACHING -- the fiber-TLS boundary the inlined rseq read needs. #### Benchmark sas2-2769 (glibc 2.31 + tcmalloc, rseq fast path), median of 5: | primitive | time | |---|---| | TTscp::Get() (rdtscp) | 14.1 ns | | TTscp::GetApproximate() (rseq + rdtsc) | 10.6 ns (-25%) | commit_hash:b277b6551accd6d0b879f8ffb168bcbe8d9fbb74

Make library/cpp/yt/rseq a Linux-only dependency of library/cpp/yt/system

2026-06-15T08:32:51Z

Make library/cpp/yt/rseq a Linux-only dependency of library/cpp/yt/system commit_hash:7d6f5e738658447529440425b55b2891f6664d81

YT-18571: Move TTscp to library/cpp/yt/system

2026-06-14T21:29:58Z

commit_hash:33721d8fd9919cec2c217db529145c881baf144b

Add library/cpp/yt/rseq: NYT::GetCurrentCpuId() via Linux rseq

2026-06-13T22:35:19Z

Self-contained current-CPU-id reader backed by Linux **rseq** (restartable sequences), with **no third-party dependency** (no librseq): * The rseq ABI is hand-defined; the calling thread is registered lazily via the rseq syscall. * Fast path is a single inlined, **branch-free** thread-local read. The offset always points at a readable `cpu_id` -- the glibc-owned area when glibc registers rseq (>= 2.35, via the weak `__rseq_offset`/`__rseq_size`), otherwise our own area -- so an unregistered thread reads `-1` and routes to the slow path. * Falls back to `sched_getcpu()` (Linux) or `0` (darwin/windows). Works on glibc **and musl** alike (librseq does not build on musl). Fiber-TLS contract: the inlined read must be reached only via a non-inlinable, fiber-switch-free frame (a virtual call or `YT_PREVENT_TLS_CACHING`). #### Benchmark -- cost of one cpu-id read | source | time / call | |---|---| | `GetCurrentCpuId()` (rseq) | **0.34 ns** | | `sched_getcpu()` (vDSO) | 3.5 ns | | `rdtscp` (what `TTscp::Get()` does) | 23 ns | This is an alternative to the librseq-based review/13886037 -- same speed, but no contrib dependency and it also covers musl. The unit test pins to each allowed CPU and asserts the reported id matches. 🤖 Generated with [Claude Code](https://claude.com/claude-code) commit_hash:09d282c2f48755836b1cd68cedbffc3c6a662eed

Cache process/thread id getters and use them in TError origin capture

2026-06-06T21:16:49Z

## Motivation Profiling the YT master Automaton thread showed TOriginAttributes::Capture (run on every non-OK TError) spending ~60% of its time in a getpid() syscall — uncached on glibc >= 2.25. NYT::GetCurrentThreadId() (gettid) feeds hot thread-affinity / log-manager checks on the same thread. ## Changes - New library/cpp/yt/system/process_id.* with cached GetProcessId(); GetSystemThreadId() now caches the kernel tid in TLS. Both caches reset in the child after fork. - Moved thread_name.{h,cpp} from misc to system. - Removed GetCurrentProcessId/GetCurrentThreadId shims from yt/yt/core/misc/proc.{h,cpp}; migrated all callers to NYT::GetProcessId / NYT::GetSystemThreadId. - TOriginAttributes::Capture uses the cached getters; recorded Tid is now the real kernel tid (matches perf/ps). - Added microbenchmarks (library/cpp/yt/system/benchmarks, yt/yt/core/benchmarks/error.cpp). ## Microbenchmarks (release) | | before | after | |---|---|---| | getpid | 101 ns | 0.33 ns | | gettid | 102 ns | 1.64 ns | | Capture | 161 ns | 50 ns | | failed TError | 221 ns | 74 ns | commit_hash:ee37ae57d61a5a2dd33daee935270f4bb93b7ff9

Generalize GetEnvValueOrThrow with a typed conversion overload

2026-06-03T08:26:50Z

Add a templated GetEnvValueOrThrow that parses the environment variable value via FromString, next to the existing std::string overload. commit_hash:0421b0463c473c8c7f88c0b1619484e52b002897

Extract environment variables helpers to library/cpp/yt/system

2026-05-01T12:04:18Z

commit_hash:5a11a7288f325d6fa0a9bec9a1ce0b7afa1f4984

YT-18571: Refactor environ helpers

2025-11-02T16:05:26Z

commit_hash:72977e13820ded4a38d19076b1d336c9bb910dbf

Refactor local host name and YP cluster functions

2025-02-02T09:43:24Z

commit_hash:a4ecfb1e06e82ba192646d3ab5417cb3f0c6991f

YT-21233: Adjust (To/From)ErrorAttributeValue CPOs, revert ConvertTo becoming CPO, move TErrorCode and TError to library/cpp/yt/error

2024-12-25T04:31:55Z

\[nodiff:caesar\] List of changes: 1) Make `ConvertTo` a normal function again (basically, a revert of previous change). It turned out to be very inconvenient entry point 2) Introduce concept for "Primitive types" which are handled without yt/core module. Please note that inclusion of core **does not** affect work with primitive types (otherwise we would be facing and ODR violation). These are numerics, duration, instant, string-like objects and guid 3) Introduce `FromErrorAttributeValue` which is a substitute to `ConvertTo` with special behavior (see below) 4) Scheme for (de-)serialization has changed: 1) Primitive types are handled via `ConvertToTextYsonString` and `ConvertFromTextYsonString` 2) Other types are not supported without yt/core. Otherwise `ConvertToYsonString(value, EYsonFormat::Text)` used for serialization and `ConvertTo(value)` for deserialization. 5) New format of attribute value storage allows to not care about concrete type of the attribute (text yson strings can be detected since they start with `\"` and deserialized so are text yson bools, everything else is already human readable). This drops dependency on `TTokenizer` 6) Some small parts (e.g. enums or constants or aliases) of yt/core/misc files were moved to library/cpp/yt/\* locations and re-included to drop dependencies of stripped\_error on them 7) `TErrorAttributes` is now a simple hash map instead of a handle to `IAttributeDictionary` 8) `ExtractFromAttributes` weak symbol is finally moved to library/cpp/yt/error due to point 9 allowing to fully drop dependency on `IAttributeDictionary`. Combined with point 7 this drops dep on yt/core/ytree altogether 9) Moved `TErrorCode` to library/cpp/yt/error. There is a logger there which forces dep on library/cpp/yt/logging. It is not required really, and can be later removed 10) Moved `TError` with format and macroes to library/cpp/yt/error. It still (and probably forever will) depend on yson. What can be done next: Switch TYsonString to TString and move ConvertTo/FromTextYsonString to library/cpp/yt/error. This would remove dep on library/cpp/yt/yson\_string commit_hash:6f11dc478ab782a1f98a5aedcd45a4800d3f4e7b