From: Evgeniy Firsov <evgeniy.firsov@sandisk.com>
Date: Mon, 26 Oct 2015 18:12:57 +0000 (-0700)
Subject: stringify: Reduce CPU usage by reusing stringstream in stringify function
X-Git-Tag: v10.0.2~159^2~1
X-Git-Url: http://git-server-git.apps.pok.os.sepia.ceph.com/?a=commitdiff_plain;h=44b14883da261172cac21c152dc8fc78ce259866;p=ceph.git

stringify: Reduce CPU usage by reusing stringstream in stringify function

About 10% CPU reduction and 10% TPS bump in CPU bound workload.

Signed-off-by: Evgeniy Firsov <evgeniy.firsov@sandisk.com>
---

diff --git a/src/include/stringify.h b/src/include/stringify.h
index 0a4c4dc5124..59b7b3fb6ac 100644
--- a/src/include/stringify.h
+++ b/src/include/stringify.h
@@ -6,7 +6,8 @@
 
 template<typename T>
 inline std::string stringify(const T& a) {
-  std::ostringstream ss;
+  static __thread std::ostringstream ss;
+  ss.str("");
   ss << a;
   return ss.str();
 }