gui: add end slot reason to slot details

Author: jherrera-jump

book/api/websocket.md

@@ -2051,6 +2051,7 @@ explicitly mentioned, skipped slots are not included.
             "max_total_microblocks": 32768
         },
         "scheduler_stats": {
+            "end_slot_reason": "timeout",
             "slot_schedule_counts": [123, 123, 123, 123, 123, 123, 123],
             "end_slot_schedule_counts": [0, 10, 0, 0, 0, 0, 0],
             "pending_smallest_cost": 3000,
@@ -2190,6 +2191,7 @@ explicitly mentioned, skipped slots are not included.
 **`SlotScheduleStats`**
 | Field                        | Type              | Description |
 |------------------------------|-------------------|-------------|
+| end_slot_reason              | `string`          | The reason pack ended packing for this leader slot. One of `"timeout"`, `"microblock_limit"`, or `"leader_switch"` |
 | slot_schedule_counts         | `number[]`        | `slot_schedule_counts[i]` is the number of transactions across the leader slot that had `["success", "fail_taken", "fail_fast_path", "fail_byte_limit", "fail_write_cost", "fail_slow_path", "fail_defer_skip"][i]` as the outcome after being scheduled. "success" means the transaction was successfully scheduled to a bank. "fail_cu_limit" means Pack skipped the transaction because it would have exceeded the block CU limit. "fail_fast_path" means Pack skipped the transaction because of account conflicts using the fast bitvector check. "fail_byte_limit" means Pack skipped the transaction because it would have exceeded the block data size limit. "fail_write_cost" means Pack skipped the transaction because it would have caused a writable account to exceed the per-account block write cost limit. "fail_slow_path" means Pack skipped the transaction because of account conflicts using the full slow check. "fail_defer_skip" means Pack skipped the transaction it previously exceeded the per-account block write cost limit too many times |
 | end_slot_schedule_counts     | `number[]`        | `end_slot_schedule_counts` has the same meaning as `slot_schedule_counts` except only transactions that occur after the last successfully scheduled transaction in the slot are counted |
 | pending_smallest_cost        | `number`          | The cost in compute units of the smallest eligible non-vote transaction in pack's transaction buffer at the end of the slot.  If the buffer is empty, then this is `null` |

src/disco/gui/fd_gui_printf.c

@@ -1552,6 +1552,21 @@ fd_gui_printf_slot_transactions_request( fd_gui_t * gui,
         jsonp_close_object( gui->http );
 
         jsonp_open_object( gui->http, "scheduler_stats" );
+          switch( lslot->scheduler_stats->end_slot_reason ) {
+            case FD_PACK_END_SLOT_REASON_TIME: {
+              jsonp_string( gui->http, "end_slot_reason", "timeout" );
+              break;
+            }
+            case FD_PACK_END_SLOT_REASON_MICROBLOCK: {
+              jsonp_string( gui->http, "end_slot_reason", "microblock_limit" );
+              break;
+            }
+            case FD_PACK_END_SLOT_REASON_LEADER_SWITCH: {
+              jsonp_string( gui->http, "end_slot_reason", "leader_switch" );
+              break;
+            }
+            default: __builtin_unreachable();
+          }
           jsonp_open_array( gui->http, "slot_schedule_counts" );
             for( ulong i = 0; i<FD_METRICS_COUNTER_PACK_TRANSACTION_SCHEDULE_CNT; i++ ) jsonp_ulong( gui->http, NULL, lslot->scheduler_stats->block_results[ i ] );
           jsonp_close_array( gui->http );

src/disco/pack/fd_pack_tile.c

@@ -397,8 +397,9 @@ log_end_block_metrics( fd_pack_ctx_t * ctx,
 }
 
 static inline void
-get_done_packing( fd_pack_ctx_t * ctx, fd_done_packing_t * done_packing ) {
+get_done_packing( fd_pack_ctx_t * ctx, fd_done_packing_t * done_packing, int reason ) {
     done_packing->microblocks_in_slot = ctx->slot_microblock_cnt;
+    done_packing->end_slot_reason = reason;
     fd_pack_get_block_limits( ctx->pack, done_packing->limits_usage, done_packing->limits );
 
 #define DELTA( mem, m ) (fd_metrics_tl[ MIDX(COUNTER, PACK, TRANSACTION_SCHEDULE_##m) ] - ctx->mem->sched_results[ FD_METRICS_ENUM_PACK_TXN_SCHEDULE_V_##m##_IDX ])
@@ -574,7 +575,7 @@ after_credit( fd_pack_ctx_t *     ctx,
     *charge_busy = 1;
 
     fd_done_packing_t * done_packing = fd_chunk_to_laddr( ctx->poh_out_mem, ctx->poh_out_chunk );
-    get_done_packing( ctx, done_packing ); /* needs to be called before fd_pack_end_block */
+    get_done_packing( ctx, done_packing, FD_PACK_END_SLOT_REASON_TIME ); /* needs to be called before fd_pack_end_block */
     fd_pack_end_block( ctx->pack );
     fd_pack_get_top_writers( ctx->pack, done_packing->limits_usage->top_writers ); /* needs to be called after fd_pack_end_block */
 
@@ -813,7 +814,7 @@ after_credit( fd_pack_ctx_t *     ctx,
     FD_MCNT_INC( PACK, MICROBLOCK_PER_BLOCK_LIMIT, 1UL );
 
     fd_done_packing_t * done_packing = fd_chunk_to_laddr( ctx->poh_out_mem, ctx->poh_out_chunk );
-    get_done_packing( ctx, done_packing );
+    get_done_packing( ctx, done_packing, FD_PACK_END_SLOT_REASON_MICROBLOCK );
     fd_pack_end_block( ctx->pack );
     fd_pack_get_top_writers( ctx->pack, done_packing->limits_usage->top_writers );
 
@@ -1027,7 +1028,7 @@ after_frag( fd_pack_ctx_t *     ctx,
 
     if( FD_UNLIKELY( ctx->leader_slot!=ULONG_MAX ) ) {
       fd_done_packing_t * done_packing = fd_chunk_to_laddr( ctx->poh_out_mem, ctx->poh_out_chunk );
-      get_done_packing( ctx, done_packing );
+      get_done_packing( ctx, done_packing, FD_PACK_END_SLOT_REASON_LEADER_SWITCH );
       fd_pack_end_block( ctx->pack );
       fd_pack_get_top_writers( ctx->pack, done_packing->limits_usage->top_writers );
 

src/disco/tiles.h

@@ -149,6 +149,10 @@ struct fd_microblock_trailer {
 };
 typedef struct fd_microblock_trailer fd_microblock_trailer_t;
 
+#define FD_PACK_END_SLOT_REASON_TIME          (1)
+#define FD_PACK_END_SLOT_REASON_MICROBLOCK    (2)
+#define FD_PACK_END_SLOT_REASON_LEADER_SWITCH (3)
+
 struct fd_done_packing {
   ulong microblocks_in_slot;
 
@@ -160,6 +164,8 @@ struct fd_done_packing {
 
   fd_pack_smallest_t pending_smallest[ 1 ];
   fd_pack_smallest_t pending_votes_smallest[ 1 ];
+
+  int end_slot_reason;
 };
 typedef struct fd_done_packing fd_done_packing_t;