From: Lukáš Ondráček <lukas.ondracek@nic.cz>
Date: Wed, 23 Oct 2024 14:02:32 +0000 (+0200)
Subject: Revert "daemon/defer: use total accounted time as KRU time"
X-Git-Tag: v6.0.9~1^2~13
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=168ad0b2058ba81598f534ac027608e05d6954e5;p=thirdparty%2Fknot-resolver.git

Revert "daemon/defer: use total accounted time as KRU time"

This reverts commit 9d4ad75d103f1fe5811a1bd2765d5fddaaab0a27.
---

diff --git a/daemon/defer.c b/daemon/defer.c
index b0375ceec..5c386eec0 100644
--- a/daemon/defer.c
+++ b/daemon/defer.c
@@ -1,4 +1,3 @@
-#include <stdatomic.h>
 #include "daemon/defer.h"
 #include "daemon/mmapped.h"
 #include "daemon/session2.h"
@@ -21,10 +20,11 @@
 #define PRIORITY_SYNC        (-1)              // no queue
 #define PRIORITY_UDP         (QUEUES_CNT - 1)  // last queue
 
-#define KRU_CAPACITY         (1<<10)
-#define MAX_DECAY            (KRU_LIMIT * 0.0006929)  // -> halving counters in 1s of accounted time
-#define BASE_PRICE(nsec)     ((uint64_t)MAX_DECAY * nsec / 1000000ll)
-// TODO reconsider time flow speed in KRU (currently sum of all-processes accounted time)
+#define KRU_CAPACITY  (1<<10)
+#define MAX_DECAY     (KRU_LIMIT * 0.0006929)  // -> halving counters in 1s
+#define TIME_MULT     1/1   // NOLINT for now, TODO improve readability
+	// max fraction of rate limit filled by one cpu (multiplies large int)
+	// TODO divide by #cpus?
 
 #define REQ_TIMEOUT           5000000 // ns (THREAD_CPUTIME), older deferred queries are dropped
 #define IDLE_TIMEOUT          1000000 // ns (THREAD_CPUTIME); if exceeded, continue processing after next poll phase
@@ -38,12 +38,10 @@ struct defer {
 	size_t capacity;
 	kru_price_t max_decay;
 	bool using_avx2;
-	_Atomic uint32_t time_now;  // shared counter incremented each msec by each process, used for kru decay only
 	_Alignas(64) uint8_t kru[];
 };
 struct defer *defer = NULL;
 struct mmapped defer_mmapped = {0};
-uint64_t kru_time_now_nsec = 0;  // total time contribution of the current process
 
 defer_sample_state_t defer_sample_state = {
 	.is_accounting = 0,
@@ -112,16 +110,7 @@ void defer_account(uint64_t nsec, union kr_sockaddr *addr, bool stream) {
 	_Alignas(16) uint8_t key[16] = {0, };
 	uint16_t max_load = 0;
 	uint8_t prefix = 0;
-	kru_price_t base_price = BASE_PRICE(nsec);
-
-	uint32_t time_now;
-	uint32_t time_now_incr = (kru_time_now_nsec + nsec) / 1000000 - kru_time_now_nsec / 1000000;
-	if (time_now_incr > 0) {
-		time_now = atomic_fetch_add_explicit(&defer->time_now, time_now_incr, memory_order_relaxed) + time_now_incr;
-	} else {
-		time_now = atomic_load_explicit(&defer->time_now, memory_order_relaxed);
-	}
-	kru_time_now_nsec += nsec;
+	kru_price_t base_price = (uint64_t)MAX_DECAY * nsec * TIME_MULT / 1000000ll;  // TODO adjust
 
 	if (addr->ip.sa_family == AF_INET6) {
 		memcpy(key, &addr->ip6.sin6_addr, 16);
@@ -131,7 +120,7 @@ void defer_account(uint64_t nsec, union kr_sockaddr *addr, bool stream) {
 			prices[i] = base_price / V6_RATE_MULT[i];
 		}
 
-		max_load = KRU.load_multi_prefix_max((struct kru *)defer->kru, time_now,
+		max_load = KRU.load_multi_prefix_max((struct kru *)defer->kru, kr_now(),
 				1, key, V6_PREFIXES, prices, V6_PREFIXES_CNT, &prefix);
 	} else if (addr->ip.sa_family == AF_INET) {
 		memcpy(key, &addr->ip4.sin_addr, 4);
@@ -141,14 +130,14 @@ void defer_account(uint64_t nsec, union kr_sockaddr *addr, bool stream) {
 			prices[i] = base_price / V4_RATE_MULT[i];
 		}
 
-		max_load = KRU.load_multi_prefix_max((struct kru *)defer->kru, time_now,
+		max_load = KRU.load_multi_prefix_max((struct kru *)defer->kru, kr_now(),
 				0, key, V4_PREFIXES, prices, V4_PREFIXES_CNT, &prefix);
 	} else {
 		return;
 	}
 
-	VERBOSE_LOG("  %s ADD %4.3f ms -> load: %d on /%d  (kru time: %d)\n",
-			kr_straddr(&defer_sample_state.addr.ip), nsec / 1000000.0, max_load, prefix, time_now);
+	VERBOSE_LOG("  %s ADD %4.3f ms -> load: %d on /%d\n",
+			kr_straddr(&defer_sample_state.addr.ip), nsec / 1000000.0, max_load, prefix);
 }
 
 /// Determine priority of the request in [-1, QUEUES_CNT - 1].
@@ -166,17 +155,16 @@ static inline int classify(const union kr_sockaddr *addr, bool stream)
 		return PRIORITY_UDP;
 	}
 
-	uint32_t time_now = atomic_load_explicit(&defer->time_now, memory_order_relaxed);
 	_Alignas(16) uint8_t key[16] = {0, };
 	uint16_t max_load = 0;
 	uint8_t prefix = 0;
 	if (addr->ip.sa_family == AF_INET6) {
 		memcpy(key, &addr->ip6.sin6_addr, 16);
-		max_load = KRU.load_multi_prefix_max((struct kru *)defer->kru, time_now,
+		max_load = KRU.load_multi_prefix_max((struct kru *)defer->kru, kr_now(),
 				1, key, V6_PREFIXES, NULL, V6_PREFIXES_CNT, &prefix);
 	} else if (addr->ip.sa_family == AF_INET) {
 		memcpy(key, &addr->ip4.sin_addr, 4);
-		max_load = KRU.load_multi_prefix_max((struct kru *)defer->kru, time_now,
+		max_load = KRU.load_multi_prefix_max((struct kru *)defer->kru, kr_now(),
 				0, key, V4_PREFIXES, NULL, V4_PREFIXES_CNT, &prefix);
 	}
 
@@ -437,7 +425,6 @@ int defer_init(uv_loop_t *loop)
 		kr_log_info(SYSTEM, "Initializing prioritization...\n");
 
 		defer = defer_mmapped.mem;
-		defer->time_now = 0;
 
 		bool succ = KRU.initialize((struct kru *)defer->kru, capacity_log, header.max_decay);
 		if (!succ) {