From mboxrd@z Thu Jan  1 00:00:00 1970
Return-Path: <mpe@ellerman.id.au>
Received: from ozlabs.org (ozlabs.org [IPv6:2401:3900:2:1::2])
 (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits))
 (No client certificate requested)
 by lists.ozlabs.org (Postfix) with ESMTPS id 43F4A1A0D6C
 for <linuxppc-dev@lists.ozlabs.org>; Wed, 21 Jan 2015 14:07:08 +1100 (AEDT)
Message-ID: <1421809627.4900.1.camel@ellerman.id.au>
Subject: Re: [PATCH] powerpc/mm: Add trace point for tracking hash pte fault
From: Michael Ellerman <mpe@ellerman.id.au>
To: "Aneesh Kumar K.V" <aneesh.kumar@linux.vnet.ibm.com>
Date: Wed, 21 Jan 2015 14:07:07 +1100
In-Reply-To: <1421753750-17135-1-git-send-email-aneesh.kumar@linux.vnet.ibm.com>
References: <1421753750-17135-1-git-send-email-aneesh.kumar@linux.vnet.ibm.com>
Content-Type: text/plain; charset="UTF-8"
Mime-Version: 1.0
Cc: paulus@samba.org, linuxppc-dev@lists.ozlabs.org
List-Id: Linux on PowerPC Developers Mail List <linuxppc-dev.lists.ozlabs.org>
List-Unsubscribe: <https://lists.ozlabs.org/options/linuxppc-dev>,
 <mailto:linuxppc-dev-request@lists.ozlabs.org?subject=unsubscribe>
List-Archive: <http://lists.ozlabs.org/pipermail/linuxppc-dev/>
List-Post: <mailto:linuxppc-dev@lists.ozlabs.org>
List-Help: <mailto:linuxppc-dev-request@lists.ozlabs.org?subject=help>
List-Subscribe: <https://lists.ozlabs.org/listinfo/linuxppc-dev>,
 <mailto:linuxppc-dev-request@lists.ozlabs.org?subject=subscribe>

On Tue, 2015-01-20 at 17:05 +0530, Aneesh Kumar K.V wrote:
> This enables us to understand how many hash fault we are taking
> when running benchmarks.
> 
> For ex:
> -bash-4.2# ./perf stat -e  powerpc:hash_fault -e page-faults /tmp/ebizzy.ppc64 -S 30  -P -n 1000
> ...
> 
>  Performance counter stats for '/tmp/ebizzy.ppc64 -S 30 -P -n 1000':
> 
>        1,10,04,075      powerpc:hash_fault
>        1,10,03,429      page-faults
> 
>       30.865978991 seconds time elapsed

Looks good.

Can you attach some test results that show it's not hurting performance when
it's disabled.

cheers