From 34bd1e0709f66fa2d32a74d1eea4f5bd7b0a6a93 Mon Sep 17 00:00:00 2001
From: Jason Volk <jason@zemos.net>
Date: Mon, 20 Feb 2023 12:19:12 -0800
Subject: [PATCH] ircd::ctx::pool: Add option for dispatch strategy; behavior
 changed by default.

---
 include/ircd/ctx/pool.h | 6 ++++++
 ircd/client.cc          | 1 +
 ircd/ctx.cc             | 7 ++++++-
 3 files changed, 13 insertions(+), 1 deletion(-)

diff --git a/include/ircd/ctx/pool.h b/include/ircd/ctx/pool.h
index eaf0c5605..ea994ed27 100644
--- a/include/ircd/ctx/pool.h
+++ b/include/ircd/ctx/pool.h
@@ -115,6 +115,12 @@ struct ircd::ctx::pool::opts
 
 	/// Scheduler priority nice value for contexts in this pool.
 	int8_t nice {0};
+
+	/// Worker dispatch strategy.
+	/// - FIFO: Dispatch fairly (round-robin).
+	/// - LIFO: Dispatch the last to finish.
+	/// - SORT: Like LIFO but lower ID's are given partial precedence.
+	dock::opts dispatch {dock::opts::LIFO};
 };
 
 template<class F,
diff --git a/ircd/client.cc b/ircd/client.cc
index fbbe8aee1..78ea75168 100644
--- a/ircd/client.cc
+++ b/ircd/client.cc
@@ -90,6 +90,7 @@ ircd::client::pool_opts
 {
 	.stack_size = size_t(settings.stack_size),
 	.initial_ctxs = size_t(settings.pool_size),
+	.dispatch = ctx::dock::opts::SORT,
 };
 
 /// The pool of request contexts. When a client makes a request it does so by acquiring
diff --git a/ircd/ctx.cc b/ircd/ctx.cc
index bec3786ef..5d947a138 100644
--- a/ircd/ctx.cc
+++ b/ircd/ctx.cc
@@ -1589,9 +1589,14 @@ void
 ircd::ctx::pool::work()
 try
 {
+	const auto pop_opts
+	{
+		opt->dispatch
+	};
+
 	const auto func
 	{
-		q.pop()
+		q.pop(pop_opts)
 	};
 
 	const scope_notify notify