Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S268664AbUILLNW (ORCPT ); Sun, 12 Sep 2004 07:13:22 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S268665AbUILLNW (ORCPT ); Sun, 12 Sep 2004 07:13:22 -0400 Received: from natsmtp00.rzone.de ([81.169.145.165]:26331 "EHLO natsmtp00.rzone.de") by vger.kernel.org with ESMTP id S268664AbUILLNT (ORCPT ); Sun, 12 Sep 2004 07:13:19 -0400 From: Arnd Bergmann To: Anton Blanchard Subject: Re: [PATCH] Yielding processor resources during lock contention Date: Sun, 12 Sep 2004 13:12:17 +0200 User-Agent: KMail/1.6.2 Cc: Zwane Mwaikambo , Linus Torvalds , Paul Mackerras , Linux Kernel , Andrew Morton , "Nakajima, Jun" , Andi Kleen , Ingo Molnar , Martin Schwidefsky , Eberhard Pasch References: <200409121210.32259.arnd@arndb.de> <20040912104306.GA25741@krispykreme> In-Reply-To: <20040912104306.GA25741@krispykreme> MIME-Version: 1.0 Content-Type: multipart/signed; protocol="application/pgp-signature"; micalg=pgp-sha1; boundary="Boundary-02=_V8CRB6ClQZpeqR1"; charset="iso-8859-15" Content-Transfer-Encoding: 7bit Message-Id: <200409121312.21358.arnd@arndb.de> Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1389 Lines: 40 --Boundary-02=_V8CRB6ClQZpeqR1 Content-Type: text/plain; charset="iso-8859-15" Content-Transfer-Encoding: 7bit Content-Disposition: inline On Sonntag, 12. September 2004 12:43, Anton Blanchard wrote: > cpu_relax doesnt tell us why we are busy looping. In this particular > case we want to pass to the hypervisor which virtual cpu we are waiting > on so the hypervisor make better scheduling decisions. Ah, interesting. I think s390 could do the same with the upcoming 5.1 release of z/VM. However, we decided to ask for an implementation of a futex hypercall instead, which lets us implement the linux spinlock as a hypervisor semaphore. > Did you manage to see any improvement by yielding to the hypervisor > in cpu_relax? I'm not sure if this has been measured, maybe Martin or Eberhard knows more. Arnd <>< --Boundary-02=_V8CRB6ClQZpeqR1 Content-Type: application/pgp-signature Content-Description: signature -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.2.4 (GNU/Linux) iD8DBQBBRC8U5t5GS2LDRf4RAtFOAJ9LxZiwPuovwKKeYhrsQN0FnbiOgACfX9Nh 2UNduPRAMB4hmVnYKRKgJ6E= =rjLq -----END PGP SIGNATURE----- --Boundary-02=_V8CRB6ClQZpeqR1-- - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/