linux-kernel - [PATCH 1/5] process_64: remove branch hint

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [thread-next>] [day] [month] [year] [list]

Message-ID: <4B0BBB93.3080307@klingt.org>
Date:	Tue, 24 Nov 2009 11:55:15 +0100
From:	Tim Blechmann <tim@...ngt.org>
To:	linux-kernel@...r.kernel.org
Subject: [PATCH 1/5] process_64: remove branch hint

branch hint profiling of my nehalem machine, showed 96% incorrect branch
hints:

 6548732 174664120  96 __switch_to                    process_64.c
   406
 6548745 174565593  96 __switch_to                    process_64.c
   410

Signed-off-by: Tim Blechmann <tim@...ngt.org>
---
 arch/x86/kernel/process_64.c |    4 ++--
 1 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/arch/x86/kernel/process_64.c b/arch/x86/kernel/process_64.c
index c8d0ece..1e2e1fe 100644
--- a/arch/x86/kernel/process_64.c
+++ b/arch/x86/kernel/process_64.c
@@ -403,11 +403,11 @@ __switch_to(struct task_struct *prev_p, struct
task_struct *next_p)
 	 * This won't pick up thread selector changes, but I guess that is ok.
 	 */
 	savesegment(es, prev->es);
-	if (unlikely(next->es | prev->es))
+	if (next->es | prev->es)
 		loadsegment(es, next->es);
  	savesegment(ds, prev->ds);
-	if (unlikely(next->ds | prev->ds))
+	if (next->ds | prev->ds)
 		loadsegment(ds, next->ds);
  -- 1.6.4.2



Download attachment "signature.asc" of type "application/pgp-signature" (198 bytes)