Merge bitcoin/bitcoin#22284: p2p, refactor: performance improvements to ProtectEvictionCandidatesByRatio()

b1d905c225e87a4a289c0cd3593c6c21cea3fba7 p2p: earlier continuation when no remaining eviction candidates (Vasil Dimov)
c9e8d8f9b168dec2bc7b845da38449e96708cf8e p2p: process more candidates per protection iteration (Jon Atack)
02e411ec456af80d1da76085a814c68bb3aca6de p2p: iterate eviction protection only on networks having candidates (Jon Atack)
5adb06457403f8c1d874e9c6748ecbb78ef8fa2b bench: add peer eviction protection benchmarks (Jon Atack)
566357f8f7471f74729297868917aa32f6d3c390 refactor: move GetRandomNodeEvictionCandidates() to test utilities (Jon Atack)

Pull request description:

  This follow-up to #21261 improves `ProtectEvictionCandidatesByRatio()` for better performance.

  Benchmarks are added; the performance improvement is between 2x and 5x for the benchmarked cases (CPU 2.50GHz, Turbo off, performance mode, Debian Clang 11 non-debug build).

  ```
  $ ./src/bench/bench_bitcoin -filter="EvictionProtection*.*"
  ```

  The refactored code is well-covered by existing unit tests and also a fuzzer.

  - `$ ./src/test/test_bitcoin -t net_peer_eviction_tests`
  - `$ FUZZ=node_eviction ./src/test/fuzz/fuzz ../qa-assets/fuzz_seed_corpus/node_eviction`

ACKs for top commit:
  klementtan:
    Tested and code review ACK b1d905c2.
  vasild:
    ACK b1d905c225e87a4a289c0cd3593c6c21cea3fba7
  jarolrod:
    ACK b1d905c225e87a4a289c0cd3593c6c21cea3fba7

Tree-SHA512: a3a6607b9ea2fec138da9780c03f63e177b6712091c5a3ddc3804b896a7585216446310280791f5e20cc023d02d2f03a4139237e12b5c1d7f2a1fa1011610e96

3 files changed, 27 insertions, 22 deletions

diff --git a/src/test/net_peer_eviction_tests.cpp b/src/test/net_peer_eviction_tests.cpp
index 4bfd487b86..5eb280b498 100644
--- a/src/test/net_peer_eviction_tests.cpp
+++ b/src/test/net_peer_eviction_tests.cpp
@@ -17,28 +17,6 @@
 
 BOOST_FIXTURE_TEST_SUITE(net_peer_eviction_tests, BasicTestingSetup)
 
-std::vector<NodeEvictionCandidate> GetRandomNodeEvictionCandidates(const int n_candidates, FastRandomContext& random_context)
-{
-    std::vector<NodeEvictionCandidate> candidates;
-    for (int id = 0; id < n_candidates; ++id) {
-        candidates.push_back({
-            /* id */ id,
-            /* nTimeConnected */ static_cast<int64_t>(random_context.randrange(100)),
-            /* m_min_ping_time */ std::chrono::microseconds{random_context.randrange(100)},
-            /* nLastBlockTime */ static_cast<int64_t>(random_context.randrange(100)),
-            /* nLastTXTime */ static_cast<int64_t>(random_context.randrange(100)),
-            /* fRelevantServices */ random_context.randbool(),
-            /* fRelayTxes */ random_context.randbool(),
-            /* fBloomFilter */ random_context.randbool(),
-            /* nKeyedNetGroup */ random_context.randrange(100),
-            /* prefer_evict */ random_context.randbool(),
-            /* m_is_local */ random_context.randbool(),
-            /* m_network */ ALL_NETWORKS[random_context.randrange(ALL_NETWORKS.size())],
-        });
-    }
-    return candidates;
-}
-
 // Create `num_peers` random nodes, apply setup function `candidate_setup_fn`,
 // call ProtectEvictionCandidatesByRatio() to apply protection logic, and then
 // return true if all of `protected_peer_ids` and none of `unprotected_peer_ids`
diff --git a/src/test/util/net.cpp b/src/test/util/net.cpp
index 847a490e03..28d7967078 100644
--- a/src/test/util/net.cpp
+++ b/src/test/util/net.cpp
@@ -6,6 +6,9 @@
 
 #include <chainparams.h>
 #include <net.h>
+#include <span.h>
+
+#include <vector>
 
 void ConnmanTestMsg::NodeReceiveMsgBytes(CNode& node, Span<const uint8_t> msg_bytes, bool& complete) const
 {
@@ -37,3 +40,25 @@ bool ConnmanTestMsg::ReceiveMsgFrom(CNode& node, CSerializedNetMsg& ser_msg) con
     NodeReceiveMsgBytes(node, ser_msg.data, complete);
     return complete;
 }
+
+std::vector<NodeEvictionCandidate> GetRandomNodeEvictionCandidates(int n_candidates, FastRandomContext& random_context)
+{
+    std::vector<NodeEvictionCandidate> candidates;
+    for (int id = 0; id < n_candidates; ++id) {
+        candidates.push_back({
+            /* id */ id,
+            /* nTimeConnected */ static_cast<int64_t>(random_context.randrange(100)),
+            /* m_min_ping_time */ std::chrono::microseconds{random_context.randrange(100)},
+            /* nLastBlockTime */ static_cast<int64_t>(random_context.randrange(100)),
+            /* nLastTXTime */ static_cast<int64_t>(random_context.randrange(100)),
+            /* fRelevantServices */ random_context.randbool(),
+            /* fRelayTxes */ random_context.randbool(),
+            /* fBloomFilter */ random_context.randbool(),
+            /* nKeyedNetGroup */ random_context.randrange(100),
+            /* prefer_evict */ random_context.randbool(),
+            /* m_is_local */ random_context.randbool(),
+            /* m_network */ ALL_NETWORKS[random_context.randrange(ALL_NETWORKS.size())],
+        });
+    }
+    return candidates;
+}
diff --git a/src/test/util/net.h b/src/test/util/net.h
index 1b49a671bd..939ec322ed 100644
--- a/src/test/util/net.h
+++ b/src/test/util/net.h
@@ -141,4 +141,6 @@ private:
     mutable size_t m_consumed;
 };
 
+std::vector<NodeEvictionCandidate> GetRandomNodeEvictionCandidates(int n_candidates, FastRandomContext& random_context);
+
 #endif // BITCOIN_TEST_UTIL_NET_H