Askrene parallel solving support

bitcoin/short_channel_id.h

@@ -17,7 +17,7 @@ static inline bool short_channel_id_eq(struct short_channel_id a,
 	return a.u64 == b.u64;
 }
 
-static inline size_t short_channel_id_hash(struct short_channel_id scid)
+static inline size_t hash_scid(struct short_channel_id scid)
 {
 	/* scids cost money to generate, so simple hash works here */
 	return (scid.u64 >> 32) ^ (scid.u64 >> 16) ^ scid.u64;
@@ -46,6 +46,12 @@ static inline bool short_channel_id_dir_eq(const struct short_channel_id_dir *a,
 	return short_channel_id_eq(a->scid, b->scid) && a->dir == b->dir;
 }
 
+static inline size_t hash_scidd(const struct short_channel_id_dir *scidd)
+{
+	/* Bottom bit is common, so use bit 4 for direction */
+	return hash_scid(scidd->scid) | (scidd->dir << 4);
+}
+
 static inline u32 short_channel_id_blocknum(struct short_channel_id scid)
 {
 	return scid.u64 >> 40;

common/gossmap.c

@@ -29,11 +29,7 @@ static bool chanidx_eq_id(const ptrint_t *pidx,
 	struct short_channel_id pidxid = chanidx_id(pidx);
 	return short_channel_id_eq(pidxid, scid);
 }
-static size_t scid_hash(const struct short_channel_id scid)
-{
-	return siphash24(siphash_seed(), &scid, sizeof(scid));
-}
-HTABLE_DEFINE_NODUPS_TYPE(ptrint_t, chanidx_id, scid_hash, chanidx_eq_id,
+HTABLE_DEFINE_NODUPS_TYPE(ptrint_t, chanidx_id, hash_scid, chanidx_eq_id,
 			  chanidx_htable);
 
 static struct node_id nodeidx_id(const ptrint_t *pidx);

connectd/connectd.h

@@ -260,7 +260,7 @@ static bool scid_to_node_id_eq_scid(const struct scid_to_node_id *scid_to_node_i
  * we use this to forward onion messages which specify the next hop by scid/dir. */
 HTABLE_DEFINE_NODUPS_TYPE(struct scid_to_node_id,
 			  scid_to_node_id_keyof,
-			  short_channel_id_hash,
+			  hash_scid,
 			  scid_to_node_id_eq_scid,
 			  scid_htable);
 

doc/lightningd-config.5.md

@@ -561,6 +561,10 @@ command, so they invoices can also be paid onchain.
 
   This option makes the `getroutes` call fail if it takes more than this many seconds.  Setting it to zero is a fun way to ensure your node never makes payments.
 
+* **askrene-max-threads**=*NUMBER* [plugin `askrene`, *dynamic*]
+
+  This option controls how many routes askrene will calculate at once: this is only useful on nodes which make multiple payments at once, and setting the number higher than your number of cores/CPUS will not help.  The default is 4.
+
 ### Networking options
 
 Note that for simple setups, the implicit *autolisten* option does the

lightningd/channel.h

@@ -891,7 +891,7 @@ static inline bool scid_to_channel_eq_scid(const struct scid_to_channel *scidcha
 /* Define channel_scid_map */
 HTABLE_DEFINE_NODUPS_TYPE(struct scid_to_channel,
 			  scid_to_channel_key,
-			  short_channel_id_hash,
+			  hash_scid,
 			  scid_to_channel_eq_scid,
 			  channel_scid_map);
 

plugins/askrene/Makefile

@@ -1,30 +1,24 @@
-PLUGIN_ASKRENE_SRC := \
+PLUGIN_ASKRENE_PARENT_SRC := \
 	plugins/askrene/askrene.c \
 	plugins/askrene/datastore_wire.c \
 	plugins/askrene/layer.c \
-	plugins/askrene/reserve.c \
-	plugins/askrene/mcf.c \
-	plugins/askrene/dijkstra.c \
-	plugins/askrene/flow.c \
-	plugins/askrene/refine.c \
-	plugins/askrene/explain_failure.c \
-	plugins/askrene/graph.c \
-	plugins/askrene/priorityqueue.c \
-	plugins/askrene/algorithm.c
+	plugins/askrene/reserve.c
 
-PLUGIN_ASKRENE_HEADER := \
-	plugins/askrene/askrene.h \
-	plugins/askrene/datastore_wire.h \
-	plugins/askrene/layer.h \
-	plugins/askrene/reserve.h \
-	plugins/askrene/mcf.h \
-	plugins/askrene/dijkstra.h \
-	plugins/askrene/flow.h \
-	plugins/askrene/refine.h \
-	plugins/askrene/explain_failure.h \
-	plugins/askrene/graph.h \
-	plugins/askrene/priorityqueue.h \
-	plugins/askrene/algorithm.h
+PLUGIN_ASKRENE_CHILD_SRC := \
+	plugins/askrene/child/child.c \
+	plugins/askrene/child/mcf.c \
+	plugins/askrene/child/dijkstra.c \
+	plugins/askrene/child/flow.c \
+	plugins/askrene/child/refine.c \
+	plugins/askrene/child/explain_failure.c \
+	plugins/askrene/child/graph.c \
+	plugins/askrene/child/priorityqueue.c \
+	plugins/askrene/child/algorithm.c \
+	plugins/askrene/child/child_log.c \
+	plugins/askrene/child/route_query.c \
+
+PLUGIN_ASKRENE_SRC := $(PLUGIN_ASKRENE_PARENT_SRC) $(PLUGIN_ASKRENE_CHILD_SRC)
+PLUGIN_ASKRENE_HEADER := $(PLUGIN_ASKRENE_SRC:.c=.h) plugins/askrene/child/additional_costs.h
 
 PLUGIN_ASKRENE_OBJS := $(PLUGIN_ASKRENE_SRC:.c=.o)