From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mx0a-001b2d01.pphosted.com (mx0b-001b2d01.pphosted.com [148.163.158.5]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by lists.ozlabs.org (Postfix) with ESMTPS id 3yBlNS59tMzDr5S for ; Wed, 11 Oct 2017 18:04:56 +1100 (AEDT) Received: from pps.filterd (m0098414.ppops.net [127.0.0.1]) by mx0b-001b2d01.pphosted.com (8.16.0.21/8.16.0.21) with SMTP id v9B73j6Z139686 for ; Wed, 11 Oct 2017 03:04:54 -0400 Received: from e06smtp15.uk.ibm.com (e06smtp15.uk.ibm.com [195.75.94.111]) by mx0b-001b2d01.pphosted.com with ESMTP id 2dhdr42c0j-1 (version=TLSv1.2 cipher=AES256-SHA bits=256 verify=NOT) for ; Wed, 11 Oct 2017 03:04:53 -0400 Received: from localhost by e06smtp15.uk.ibm.com with IBM ESMTP SMTP Gateway: Authorized Use Only! Violators will be prosecuted for from ; Wed, 11 Oct 2017 08:04:52 +0100 Received: from d23av04.au.ibm.com (d23av04.au.ibm.com [9.190.235.139]) by b06cxnps3074.portsmouth.uk.ibm.com (8.14.9/8.14.9/NCO v10.0) with ESMTP id v9B74lUI25624762 for ; Wed, 11 Oct 2017 07:04:49 GMT Received: from d23av04.au.ibm.com (localhost [127.0.0.1]) by d23av04.au.ibm.com (8.14.4/8.14.4/NCO v10.0 AVout) with ESMTP id v9B74ooE016004 for ; Wed, 11 Oct 2017 18:04:51 +1100 Date: Wed, 11 Oct 2017 12:34:43 +0530 From: "Naveen N. Rao" To: Santosh Sivaraj Cc: linuxppc-dev , Michael Ellerman , John Stultz , Thomas Gleixner , Frederic Weisbecker , Srikar Dronamraju , Benjamin Herrenschmidt Subject: Re: [PATCH v6] powerpc/vdso64: Add support for CLOCK_{REALTIME/MONOTONIC}_COARSE References: <20171010093033.73x66lxl3xxi33qo@naverao1-tp.localdomain> <20171010231003.10325-1-santosh@fossix.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii In-Reply-To: <20171010231003.10325-1-santosh@fossix.org> Message-Id: <20171011070443.5lupjenfs4ycwd5q@naverao1-tp.localdomain> List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Hi Santosh, This seems to have gone from v4 to v6 -- did I miss v5? On 2017/10/10 11:10PM, Santosh Sivaraj wrote: > Current vDSO64 implementation does not have support for coarse clocks > (CLOCK_MONOTONIC_COARSE, CLOCK_REALTIME_COARSE), for which it falls back > to system call, increasing the response time, vDSO implementation reduces > the cycle time. Below is a benchmark of the difference in execution times. > > (Non-coarse clocks are also included just for completion) > > clock-gettime-realtime: syscall: 172 nsec/call > clock-gettime-realtime: libc: 28 nsec/call > clock-gettime-realtime: vdso: 22 nsec/call > clock-gettime-monotonic: syscall: 171 nsec/call > clock-gettime-monotonic: libc: 30 nsec/call > clock-gettime-monotonic: vdso: 25 nsec/call > clock-gettime-realtime-coarse: syscall: 153 nsec/call > clock-gettime-realtime-coarse: libc: 16 nsec/call > clock-gettime-realtime-coarse: vdso: 10 nsec/call > clock-gettime-monotonic-coarse: syscall: 167 nsec/call > clock-gettime-monotonic-coarse: libc: 17 nsec/call > clock-gettime-monotonic-coarse: vdso: 11 nsec/call > > CC: Benjamin Herrenschmidt > Signed-off-by: Santosh Sivaraj > --- > arch/powerpc/kernel/asm-offsets.c | 2 + > arch/powerpc/kernel/vdso64/gettimeofday.S | 67 ++++++++++++++++++++++++++----- > 2 files changed, 58 insertions(+), 11 deletions(-) ... and no changes since the last rev? It is better to post new versions in a separate thread and to include the changelog for easier review. - Naveen