From 2c111cff3015b80a86ab16d3f1edee934bc25e59 Mon Sep 17 00:00:00 2001
From: Sara Golemon <sgolemon@fb.com>
Date: Wed, 24 Jun 2015 10:48:20 -0700
Subject: [PATCH] Don't hardcode thread limit in ServerBootstrap

Summary: This was set to 32 which probably works fine for the
majority of FB servers, but not everyone's system is so endowed.

Closes #119

Reviewed By: @fredemmott

Differential Revision: D2187008
---
 folly/wangle/bootstrap/ServerBootstrap.h | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/folly/wangle/bootstrap/ServerBootstrap.h b/folly/wangle/bootstrap/ServerBootstrap.h
index 3b7f6b0a..2c2a6b47 100644
--- a/folly/wangle/bootstrap/ServerBootstrap.h
+++ b/folly/wangle/bootstrap/ServerBootstrap.h
@@ -120,8 +120,13 @@ class ServerBootstrap {
         1, std::make_shared<wangle::NamedThreadFactory>("Acceptor Thread"));
     }
     if (!io_group) {
+      auto threads = std::thread::hardware_concurrency();
+      if (threads <= 0) {
+        // Reasonable mid-point for concurrency when actual value unknown
+        threads = 8;
+      }
       io_group = std::make_shared<folly::wangle::IOThreadPoolExecutor>(
-        32, std::make_shared<wangle::NamedThreadFactory>("IO Thread"));
+        threads, std::make_shared<wangle::NamedThreadFactory>("IO Thread"));
     }
 
     // TODO better config checking
-- 
2.34.1