From 8860e027a888e67936c096c7c5dc81806f6665bf Mon Sep 17 00:00:00 2001
From: William Banfield <4561443+williambanfield@users.noreply.github.com>
Date: Tue, 21 Jun 2022 20:51:09 -0400
Subject: [PATCH] p2p: more dial routines (#8827)

The dial routines perform network i/o, which is a blocking call into the kernel. These routines are completely unable to do anything else while the dial occurs, so for most of their lifecycle they are sitting idle waiting for the tcp stack to hand them data. We should increase this value by _a lot_ to enable more concurrent dials. This is unlikely to cause CPU starvation because these routines sit idle most of the time. The current value causes dials to occur _way_ too slowly.

Below is a graph demonstrating the before and after of this change in a testnetwork with many dead peers. You can observe that the rate that we connect to new, valid peers, is _much_ higher than previously. Change was deployed around the 31 minute mark on the graph.

![image](https://user-images.githubusercontent.com/4561443/174919007-50e4453a-edd8-41d0-97ee-dea8853d57f7.png)
---
 internal/p2p/router.go | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/internal/p2p/router.go b/internal/p2p/router.go
index ff90e8c21..7ad5529fb 100644
--- a/internal/p2p/router.go
+++ b/internal/p2p/router.go
@@ -417,7 +417,7 @@ func (r *Router) routeChannel(
 
 func (r *Router) numConcurrentDials() int {
 	if r.options.NumConcurrentDials == nil {
-		return runtime.NumCPU()
+		return runtime.NumCPU() * 32
 	}
 
 	return r.options.NumConcurrentDials()