From f28b47bd87855f2c59786f2f6ac4401e3ef3681d Mon Sep 17 00:00:00 2001
From: Nishant Das <nishdas93@gmail.com>
Date: Fri, 20 May 2022 16:12:52 +0800
Subject: [PATCH] Raise Soft File Descriptor Limit Up To The Hard Limit
 (#10650)

* add changes

* comment

* kasey's review

Co-authored-by: prylabs-bulldozer[bot] <58059840+prylabs-bulldozer[bot]@users.noreply.github.com>
---
 cmd/beacon-chain/BUILD.bazel      |  1 +
 cmd/beacon-chain/main.go          |  4 ++++
 runtime/fdlimits/BUILD.bazel      | 22 ++++++++++++++++++++++
 runtime/fdlimits/fdlimits.go      | 25 +++++++++++++++++++++++++
 runtime/fdlimits/fdlimits_test.go | 22 ++++++++++++++++++++++
 5 files changed, 74 insertions(+)
 create mode 100644 runtime/fdlimits/BUILD.bazel
 create mode 100644 runtime/fdlimits/fdlimits.go
 create mode 100644 runtime/fdlimits/fdlimits_test.go

diff --git a/cmd/beacon-chain/BUILD.bazel b/cmd/beacon-chain/BUILD.bazel
index 0a459e3f1..9696d754a 100644
--- a/cmd/beacon-chain/BUILD.bazel
+++ b/cmd/beacon-chain/BUILD.bazel
@@ -28,6 +28,7 @@ go_library(
         "//io/logs:go_default_library",
         "//monitoring/journald:go_default_library",
         "//runtime/debug:go_default_library",
+        "//runtime/fdlimits:go_default_library",
         "//runtime/maxprocs:go_default_library",
         "//runtime/tos:go_default_library",
         "//runtime/version:go_default_library",
diff --git a/cmd/beacon-chain/main.go b/cmd/beacon-chain/main.go
index 0bad5b33c..60fabd72a 100644
--- a/cmd/beacon-chain/main.go
+++ b/cmd/beacon-chain/main.go
@@ -24,6 +24,7 @@ import (
 	"github.com/prysmaticlabs/prysm/io/logs"
 	"github.com/prysmaticlabs/prysm/monitoring/journald"
 	"github.com/prysmaticlabs/prysm/runtime/debug"
+	"github.com/prysmaticlabs/prysm/runtime/fdlimits"
 	_ "github.com/prysmaticlabs/prysm/runtime/maxprocs"
 	"github.com/prysmaticlabs/prysm/runtime/tos"
 	"github.com/prysmaticlabs/prysm/runtime/version"
@@ -193,6 +194,9 @@ func main() {
 		if err := debug.Setup(ctx); err != nil {
 			return err
 		}
+		if err := fdlimits.SetMaxFdLimits(); err != nil {
+			return err
+		}
 		return cmd.ValidateNoArgs(ctx)
 	}
 
diff --git a/runtime/fdlimits/BUILD.bazel b/runtime/fdlimits/BUILD.bazel
new file mode 100644
index 000000000..87350dde1
--- /dev/null
+++ b/runtime/fdlimits/BUILD.bazel
@@ -0,0 +1,22 @@
+load("@prysm//tools/go:def.bzl", "go_library", "go_test")
+
+go_library(
+    name = "go_default_library",
+    srcs = ["fdlimits.go"],
+    importpath = "github.com/prysmaticlabs/prysm/runtime/fdlimits",
+    visibility = ["//visibility:public"],
+    deps = [
+        "@com_github_ethereum_go_ethereum//common/fdlimit:go_default_library",
+        "@com_github_sirupsen_logrus//:go_default_library",
+    ],
+)
+
+go_test(
+    name = "go_default_test",
+    srcs = ["fdlimits_test.go"],
+    deps = [
+        ":go_default_library",
+        "//testing/assert:go_default_library",
+        "@com_github_ethereum_go_ethereum//common/fdlimit:go_default_library",
+    ],
+)
diff --git a/runtime/fdlimits/fdlimits.go b/runtime/fdlimits/fdlimits.go
new file mode 100644
index 000000000..ea2289c3b
--- /dev/null
+++ b/runtime/fdlimits/fdlimits.go
@@ -0,0 +1,25 @@
+package fdlimits
+
+import (
+	"github.com/ethereum/go-ethereum/common/fdlimit"
+	log "github.com/sirupsen/logrus"
+)
+
+// SetMaxFdLimits is a wrapper around a few go-ethereum methods to allow prysm to
+// set its file descriptor limits at the maximum possible value.
+func SetMaxFdLimits() error {
+	curr, err := fdlimit.Current()
+	if err != nil {
+		return err
+	}
+	max, err := fdlimit.Maximum()
+	if err != nil {
+		return err
+	}
+	raisedVal, err := fdlimit.Raise(uint64(max))
+	if err != nil {
+		return err
+	}
+	log.Infof("Raised fd limit to %d from %d", raisedVal, curr)
+	return nil
+}
diff --git a/runtime/fdlimits/fdlimits_test.go b/runtime/fdlimits/fdlimits_test.go
new file mode 100644
index 000000000..d608a0d81
--- /dev/null
+++ b/runtime/fdlimits/fdlimits_test.go
@@ -0,0 +1,22 @@
+package fdlimits_test
+
+import (
+	"testing"
+
+	gethLimit "github.com/ethereum/go-ethereum/common/fdlimit"
+	"github.com/prysmaticlabs/prysm/runtime/fdlimits"
+	"github.com/prysmaticlabs/prysm/testing/assert"
+)
+
+func TestSetMaxFdLimits(t *testing.T) {
+	assert.NoError(t, fdlimits.SetMaxFdLimits())
+
+	curr, err := gethLimit.Current()
+	assert.NoError(t, err)
+
+	max, err := gethLimit.Maximum()
+	assert.NoError(t, err)
+
+	assert.Equal(t, max, curr, "current and maximum file descriptor limits do not match up.")
+
+}