From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from e38.co.us.ibm.com (e38.co.us.ibm.com [32.97.110.159]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (Client CN "e38.co.us.ibm.com", Issuer "GeoTrust SSL CA" (not verified)) by ozlabs.org (Postfix) with ESMTPS id E37612C0326 for ; Fri, 2 Nov 2012 12:20:44 +1100 (EST) Received: from /spool/local by e38.co.us.ibm.com with IBM ESMTP SMTP Gateway: Authorized Use Only! Violators will be prosecuted for from ; Thu, 1 Nov 2012 19:20:42 -0600 Received: from d03relay05.boulder.ibm.com (d03relay05.boulder.ibm.com [9.17.195.107]) by d03dlp03.boulder.ibm.com (Postfix) with ESMTP id E199319D8046 for ; Thu, 1 Nov 2012 19:20:19 -0600 (MDT) Received: from d03av03.boulder.ibm.com (d03av03.boulder.ibm.com [9.17.195.169]) by d03relay05.boulder.ibm.com (8.13.8/8.13.8/NCO v10.0) with ESMTP id qA21KJsZ262436 for ; Thu, 1 Nov 2012 19:20:19 -0600 Received: from d03av03.boulder.ibm.com (loopback [127.0.0.1]) by d03av03.boulder.ibm.com (8.14.4/8.13.1/NCO v10.0 AVout) with ESMTP id qA21KIJJ010573 for ; Thu, 1 Nov 2012 19:20:19 -0600 Message-ID: <50931FD1.6040905@linux.vnet.ibm.com> Date: Thu, 01 Nov 2012 18:20:17 -0700 From: Haren Myneni MIME-Version: 1.0 To: Michael Neuling Subject: Re: [PATCH 0/6] powerpc: SMT priority (PPR) save and restore References: <1351666171.32304.10.camel@hbabu-laptop> <25370.1351730689@neuling.org> In-Reply-To: <25370.1351730689@neuling.org> Content-Type: text/plain; charset=ISO-8859-1 Cc: linuxppc-dev@lists.ozlabs.org, anton@au1.ibm.com, paulus@samba.org List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , On 10/31/2012 05:44 PM, Michael Neuling wrote: > Haren Myneni wrote: > >> [PATCH 0/6] powerpc: SMT priority (PPR) save and restore >> >> On P7 systems, users can define SMT priority levels 2,3 and 4 for >> processes so that some can run higher priority than the other ones. >> In the current kernel, the default priority is set to 4 which prohibits >> processes for using higher priority. Also the kernel boosts the priority to >> 4 during exceptions without saving the user defined priorities when >> the task enters the kernel. So we will be loosing the process PPR value >> and can not be restored it back when the task exits the kernel. >> >> This patchset implements saving and restore the user defined PPR value >> for all tasks. >> >> With null_syscall testcase (http://ozlabs.org/~anton/junkcode/null_syscall.c), >> this feature takes around extra 10 CPU cycles on average for 25 samples. > > Haren, > > This version doesn't do PPR save/restore over syscall, so is this above > statement still true? null_syscall shouldn't be effected at all, right? > > Mikey > Mikey, Yes this version does not save/ restore for syscall entries. But we set default priority 3 for each syscall exit - set HMT_MEDIUM_LOW for normal return, and set 3 in thread.ppr so that this value will be set for fast return path. So I was using null_syscall test case to find out the performance overhead with this patch-set. Thanks Haren >> >> Haren Myneni (6): >> powerpc: Move branch instruction from ACCOUNT_CPU_USER_ENTRY to caller >> powerpc: Define CPU_FTR_HAS_PPR >> powerpc: Increase exceptions arrays in paca struct to save PPR >> powerpc: Define ppr in thread_struct >> powerpc: Macros for saving/restore PPR >> powerpc: Implement PPR save/restore >> >> arch/powerpc/include/asm/cputable.h | 6 ++- >> arch/powerpc/include/asm/exception-64s.h | 45 ++++++++++++++++++++++++++---- >> arch/powerpc/include/asm/paca.h | 6 ++-- >> arch/powerpc/include/asm/ppc_asm.h | 27 ++++++++++++++++- >> arch/powerpc/include/asm/processor.h | 6 ++++ >> arch/powerpc/include/asm/reg.h | 1 + >> arch/powerpc/kernel/asm-offsets.c | 1 + >> arch/powerpc/kernel/entry_64.S | 6 +++- >> arch/powerpc/kernel/exceptions-64e.S | 3 +- >> arch/powerpc/kernel/exceptions-64s.S | 15 +++++---- >> arch/powerpc/kernel/process.c | 2 + >> 11 files changed, 96 insertions(+), 22 deletions(-) >> >> >> > _______________________________________________ > Linuxppc-dev mailing list > Linuxppc-dev@lists.ozlabs.org > https://lists.ozlabs.org/listinfo/linuxppc-dev >