perf(p2p/conn): Remove a minint call that was appearing in write pack…

…et delays (backport cometbft#2952) (cometbft#2975) (#42)

Somehow this minint call is appearing in CPU profiles. Its too large of
an appearance to be declared as noise, but I really don't get why its
there. Must be some weird system effect I don't get. (perhaps due to
being the result of a function call for a slice index? idk)

This PR just removes the function call, since its not needed, as we
already branch on the if statement.

Profile showing it:

![image](https://github.com/cometbft/cometbft/assets/6440154/a12c8918-e4ce-4a3d-bad4-5ae678988f94)

Contributes a 3% improvement to cometbft#2951

---

#### PR checklist

- [x] Tests written/updated - fully compatible with what already exists
- [x] Changelog entry added in `.changelog` (we use
[unclog](https://github.com/informalsystems/unclog) to manage our
changelog)
- [x] Updated relevant documentation (`docs/` or `spec/`) and code
comments
- [x] Title follows the [Conventional
Commits](https://www.conventionalcommits.org/en/v1.0.0/) spec
<hr>This is an automatic backport of pull request cometbft#2952 done by
[Mergify](https://mergify.com).

---------

Co-authored-by: mergify[bot] <37929162+mergify[bot]@users.noreply.github.com>
Co-authored-by: Dev Ojha <[email protected]>
Co-authored-by: Anton Kaliaev <[email protected]>
(cherry picked from commit 9ee1d13)

.changelog/unreleased/improvements/2952-lower-next-packet-msg-time.md

@@ -0,0 +1,2 @@
+- `[p2p/conn]` Minor speedup (3%) to connection.WritePacketMsgTo, by removing MinInt calls.
+  ([\#2952](https://github.com/cometbft/cometbft/pull/2952))

p2p/conn/connection.go

@@ -16,7 +16,6 @@ import (
 
 	flow "github.com/cometbft/cometbft/libs/flowrate"
 	"github.com/cometbft/cometbft/libs/log"
-	cmtmath "github.com/cometbft/cometbft/libs/math"
 	"github.com/cometbft/cometbft/libs/protoio"
 	"github.com/cometbft/cometbft/libs/service"
 	cmtsync "github.com/cometbft/cometbft/libs/sync"
@@ -830,14 +829,15 @@ func (ch *Channel) isSendPending() bool {
 func (ch *Channel) nextPacketMsg() tmp2p.PacketMsg {
 	packet := tmp2p.PacketMsg{ChannelID: int32(ch.desc.ID)}
 	maxSize := ch.maxPacketMsgPayloadSize
-	packet.Data = ch.sending[:cmtmath.MinInt(maxSize, len(ch.sending))]
 	if len(ch.sending) <= maxSize {
+		packet.Data = ch.sending
 		packet.EOF = true
 		ch.sending = nil
 		atomic.AddInt32(&ch.sendQueueSize, -1) // decrement sendQueueSize
 	} else {
+		packet.Data = ch.sending[:maxSize]
 		packet.EOF = false
-		ch.sending = ch.sending[cmtmath.MinInt(maxSize, len(ch.sending)):]
+		ch.sending = ch.sending[maxSize:]
 	}
 	return packet
 }