Rongsong Shen
729055a37f
drive_async_liveness_reserved = max(1, min(n_peers-1, n_vcpus-1)) — single source of truth for VTASK_LIVENESS_RESERVED (deadlock-freedom floor applied last). New DEFAULT_CONNECT_TIMEOUT_MS / DEFAULT_SLOWLANE_* constants. Resolved reservation logged at init; under-provisioned (n_vcpus<n_peers) clamp WARNs loudly, never self-terminates. 8 unit cases, mutation-verified.
97 lines
3.7 KiB
C
97 lines
3.7 KiB
C
#define _GNU_SOURCE
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#include <stdio.h>
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#include <unity/unity.h>
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#include "config.h"
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#include "ha.h"
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/* ====================================================================
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* raft-drive-async task 1.1 — drive-async configuration constants and
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* the peer-scaled liveness-reservation clamp helper.
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*
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* Helper under test:
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* int drive_async_liveness_reserved(int n_peers, int n_vcpus);
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*
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* Formula (design "LivenessAdmission → Sizing (peer-scaled)"):
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* VTASK_LIVENESS_RESERVED = clamp(n_peers - 1, 1, n_vcpus - 1)
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* = max(1, min(n_peers - 1, n_vcpus - 1))
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* floor 1 -> deadlock-freedom (always >=1 guaranteed-free worker)
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* ceiling n_vcpus - 1 -> keep >=1 REQ_BLOCK (commit) slot, cap never 0
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* The floor is applied LAST so it always wins (the hard correctness invariant).
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* ==================================================================== */
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/* ── Regime 1: normal n_peers-1 (the un-clamped middle) ───────────── */
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static void test_liveness_reserved_normal_three_peers(void)
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{
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/* 3-node cluster, 8 vcpus: n_peers-1 = 2, well under ceiling 7. */
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TEST_ASSERT_EQUAL_INT(2, drive_async_liveness_reserved(3, 8));
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}
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static void test_liveness_reserved_normal_five_peers(void)
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{
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/* 5-node cluster, 8 vcpus: n_peers-1 = 4, under ceiling 7. */
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TEST_ASSERT_EQUAL_INT(4, drive_async_liveness_reserved(5, 8));
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}
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/* ── Regime 2: floor hit (n_peers-1 would be < 1) ─────────────────── */
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static void test_liveness_reserved_floor_single_node(void)
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{
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/* n_peers=1 -> n_peers-1 = 0 -> floor 1 must win. */
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TEST_ASSERT_EQUAL_INT(1, drive_async_liveness_reserved(1, 8));
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}
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static void test_liveness_reserved_floor_zero_peers(void)
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{
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/* Degenerate n_peers=0 -> n_peers-1 = -1 -> floor 1 must win. */
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TEST_ASSERT_EQUAL_INT(1, drive_async_liveness_reserved(0, 8));
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}
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/* ── Regime 3: ceiling / clamp hit (under-provisioned: n_vcpus < n_peers) ── */
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static void test_liveness_reserved_ceiling_clamps_below_npeers(void)
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{
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/* n_peers=5, n_vcpus=3: n_peers-1 = 4 clamped to ceiling n_vcpus-1 = 2. */
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TEST_ASSERT_EQUAL_INT(2, drive_async_liveness_reserved(5, 3));
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}
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static void test_liveness_reserved_ceiling_floor_wins_one_vcpu(void)
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{
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/* n_vcpus=1 -> ceiling n_vcpus-1 = 0, but the floor of 1 must win:
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* max(1, min(n_peers-1, 0)) = max(1, 0) = 1. Never returns 0. */
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TEST_ASSERT_EQUAL_INT(1, drive_async_liveness_reserved(5, 1));
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}
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static void test_liveness_reserved_exactly_npeers_vcpus(void)
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{
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/* n_vcpus == n_peers: ceiling = n_vcpus-1 = n_peers-1 -> no clamp.
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* 3 peers, 3 vcpus -> min(2, 2) = 2. */
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TEST_ASSERT_EQUAL_INT(2, drive_async_liveness_reserved(3, 3));
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}
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static void test_liveness_reserved_never_exceeds_vcpus_minus_one(void)
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{
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/* Invariant: result <= n_vcpus-1 keeps >=1 commit slot (cap never 0). */
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for (int p = 0; p <= 8; p++) {
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for (int v = 1; v <= 8; v++) {
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int r = drive_async_liveness_reserved(p, v);
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TEST_ASSERT_TRUE_MESSAGE(r >= 1, "reservation floor 1 violated");
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TEST_ASSERT_TRUE_MESSAGE(r <= (v - 1 > 0 ? v - 1 : 1),
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"reservation must keep >=1 commit slot");
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}
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}
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}
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void test_drive_async_config(void)
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{
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RUN_TEST(test_liveness_reserved_normal_three_peers);
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RUN_TEST(test_liveness_reserved_normal_five_peers);
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RUN_TEST(test_liveness_reserved_floor_single_node);
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RUN_TEST(test_liveness_reserved_floor_zero_peers);
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RUN_TEST(test_liveness_reserved_ceiling_clamps_below_npeers);
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RUN_TEST(test_liveness_reserved_ceiling_floor_wins_one_vcpu);
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RUN_TEST(test_liveness_reserved_exactly_npeers_vcpus);
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RUN_TEST(test_liveness_reserved_never_exceeds_vcpus_minus_one);
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}
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