From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from aserp2120.oracle.com (aserp2120.oracle.com [141.146.126.78]) by sourceware.org (Postfix) with ESMTPS id 30F023851C13 for ; Tue, 12 Jan 2021 20:34:12 +0000 (GMT) DMARC-Filter: OpenDMARC Filter v1.3.2 sourceware.org 30F023851C13 Received: from pps.filterd (aserp2120.oracle.com [127.0.0.1]) by aserp2120.oracle.com (8.16.0.42/8.16.0.42) with SMTP id 10CKY1Bp087007; Tue, 12 Jan 2021 20:34:07 GMT Received: from userp3020.oracle.com (userp3020.oracle.com [156.151.31.79]) by aserp2120.oracle.com with ESMTP id 360kcyrcmu-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Tue, 12 Jan 2021 20:34:07 +0000 Received: from pps.filterd (userp3020.oracle.com [127.0.0.1]) by userp3020.oracle.com (8.16.0.42/8.16.0.42) with SMTP id 10CKUXIg035670; Tue, 12 Jan 2021 20:34:06 GMT Received: from userv0121.oracle.com (userv0121.oracle.com [156.151.31.72]) by userp3020.oracle.com with ESMTP id 360kf62wu9-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Tue, 12 Jan 2021 20:34:06 +0000 Received: from abhmp0009.oracle.com (abhmp0009.oracle.com [141.146.116.15]) by userv0121.oracle.com (8.14.4/8.13.8) with ESMTP id 10CKY5aH022049; Tue, 12 Jan 2021 20:34:05 GMT Received: from dhcp-10-154-97-123.vpn.oracle.com (/10.154.97.123) by default (Oracle Beehive Gateway v4.0) with ESMTP ; Tue, 12 Jan 2021 12:34:05 -0800 Content-Type: text/plain; charset=utf-8 Mime-Version: 1.0 (Mac OS X Mail 13.4 \(3608.120.23.2.4\)) Subject: Re: The performance data for two different implementation of new security feature -ftrivial-auto-var-init From: Qing Zhao In-Reply-To: <5A0F7219-DAFA-4EAA-B845-0E236A108738@ORACLE.COM> Date: Tue, 12 Jan 2021 14:34:04 -0600 Cc: Richard Biener via Gcc-patches Content-Transfer-Encoding: quoted-printable Message-Id: References: <217BE64F-A623-4453-B45B-D38B66B71B72@ORACLE.COM> <33955130-9D2D-43D5-818D-1DCC13FC1988@ORACLE.COM> <89D58812-0F3E-47AE-95A5-0A07B66EED8C@ORACLE.COM> <9585CBB2-0082-4B9A-AC75-250F54F0797C@ORACLE.COM> <51911859-45D5-4566-B588-F828B9D7313B@ORACLE.COM> <9127AAB9-92C8-4A1B-BAD5-2F5F8762DCF9@ORACLE.COM> <5A0F7219-DAFA-4EAA-B845-0E236A108738@ORACLE.COM> To: Richard Biener , Richard Sandiford X-Mailer: Apple Mail (2.3608.120.23.2.4) X-Proofpoint-Virus-Version: vendor=nai engine=6000 definitions=9862 signatures=668683 X-Proofpoint-Spam-Details: rule=notspam policy=default score=0 suspectscore=0 malwarescore=0 mlxlogscore=999 phishscore=0 bulkscore=0 spamscore=0 mlxscore=0 adultscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2009150000 definitions=main-2101120121 X-Proofpoint-Virus-Version: vendor=nai engine=6000 definitions=9862 signatures=668683 X-Proofpoint-Spam-Details: rule=notspam policy=default score=0 spamscore=0 phishscore=0 impostorscore=0 bulkscore=0 adultscore=0 suspectscore=0 malwarescore=0 lowpriorityscore=0 clxscore=1015 mlxlogscore=999 mlxscore=0 priorityscore=1501 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2009150000 definitions=main-2101120122 X-Spam-Status: No, score=-3.9 required=5.0 tests=BAYES_00, DKIMWL_WL_HIGH, DKIM_SIGNED, DKIM_VALID, DKIM_VALID_AU, DKIM_VALID_EF, RCVD_IN_MSPIKE_H2, SPF_HELO_PASS, SPF_PASS, TXREP, UNPARSEABLE_RELAY autolearn=ham autolearn_force=no version=3.4.2 X-Spam-Checker-Version: SpamAssassin 3.4.2 (2018-09-13) on server2.sourceware.org X-BeenThere: gcc-patches@gcc.gnu.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Gcc-patches mailing list List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Tue, 12 Jan 2021 20:34:14 -0000 Hi,=20 Just check in to see whether you have any comments and suggestions on = this: FYI, I have been continue with Approach D implementation since last = week: D. Adding calls to .DEFFERED_INIT during gimplification, expand the = .DEFFERED_INIT during expand to real initialization. Adjusting uninitialized pass with the new refs with = =E2=80=9C.DEFFERED_INIT=E2=80=9D. For the remaining work of Approach D: ** complete the implementation of -ftrivial-auto-var-init=3Dpattern; ** complete the implementation of uninitialized warnings maintenance = work for D.=20 I have completed the uninitialized warnings maintenance work for D. And finished partial of the -ftrivial-auto-var-init=3Dpattern = implementation.=20 The following are remaining work of Approach D: ** -ftrivial-auto-var-init=3Dpattern for VLA; **add a new attribute for variable: __attribute((uninitialized) the marked variable is uninitialized intentionaly for performance = purpose. ** adding complete testing cases; =20 Please let me know if you have any objection on my current decision on = implementing approach D.=20 Thanks a lot for your help. Qing > On Jan 5, 2021, at 1:05 PM, Qing Zhao via Gcc-patches = wrote: >=20 > Hi, >=20 > This is an update for our previous discussion.=20 >=20 > 1. I implemented the following two different implementations in the = latest upstream gcc: >=20 > A. Adding real initialization during gimplification, not maintain the = uninitialized warnings. >=20 > D. Adding calls to .DEFFERED_INIT during gimplification, expand the = .DEFFERED_INIT during expand to > real initialization. Adjusting uninitialized pass with the new refs = with =E2=80=9C.DEFFERED_INIT=E2=80=9D. >=20 > Note, in this initial implementation, > ** I ONLY implement -ftrivial-auto-var-init=3Dzero, the = implementation of -ftrivial-auto-var-init=3Dpattern=20 > is not done yet. Therefore, the performance data is only = about -ftrivial-auto-var-init=3Dzero.=20 >=20 > ** I added an temporary option -fauto-var-init-approach=3DA|B|C|D= to choose implementation A or D for=20 > runtime performance study. > ** I didn=E2=80=99t finish the uninitialized warnings = maintenance work for D. (That might take more time than I expected).=20 >=20 > 2. I collected runtime data for CPU2017 on a x86 machine with this new = gcc for the following 3 cases: >=20 > no: default. (-g -O2 -march=3Dnative ) > A: default + -ftrivial-auto-var-init=3Dzero = -fauto-var-init-approach=3DA=20 > D: default + -ftrivial-auto-var-init=3Dzero = -fauto-var-init-approach=3DD=20 >=20 > And then compute the slowdown data for both A and D as following: >=20 > benchmarks A / no D /no >=20 > 500.perlbench_r 1.25% 1.25% > 502.gcc_r 0.68% 1.80% > 505.mcf_r 0.68% 0.14% > 520.omnetpp_r 4.83% 4.68% > 523.xalancbmk_r 0.18% 1.96% > 525.x264_r 1.55% 2.07% > 531.deepsjeng_ 11.57% 11.85% > 541.leela_r 0.64% 0.80% > 557.xz_ -0.41% -0.41% >=20 > 507.cactuBSSN_r 0.44% 0.44% > 508.namd_r 0.34% 0.34% > 510.parest_r 0.17% 0.25% > 511.povray_r 56.57% 57.27% > 519.lbm_r 0.00% 0.00% > 521.wrf_r -0.28% -0.37% > 526.blender_r 16.96% 17.71% > 527.cam4_r 0.70% 0.53% > 538.imagick_r 2.40% 2.40% > 544.nab_r 0.00% -0.65% >=20 > avg 5.17% 5.37% >=20 > =46rom the above data, we can see that in general, the runtime = performance slowdown for=20 > implementation A and D are similar for individual benchmarks. >=20 > There are several benchmarks that have significant slowdown with the = new added initialization for both > A and D, for example, 511.povray_r, 526.blender_, and 531.deepsjeng_r, = I will try to study a little bit > more on what kind of new initializations introduced such slowdown.=20 >=20 > =46rom the current study so far, I think that approach D should be = good enough for our final implementation.=20 > So, I will try to finish approach D with the following remaining work >=20 > ** complete the implementation of = -ftrivial-auto-var-init=3Dpattern; > ** complete the implementation of uninitialized warnings = maintenance work for D.=20 >=20 >=20 > Let me know if you have any comments and suggestions on my current and = future work. >=20 > Thanks a lot for your help. >=20 > Qing >=20 >> On Dec 9, 2020, at 10:18 AM, Qing Zhao via Gcc-patches = wrote: >>=20 >> The following are the approaches I will implement and compare: >>=20 >> Our final goal is to keep the uninitialized warning and minimize the = run-time performance cost. >>=20 >> A. Adding real initialization during gimplification, not maintain the = uninitialized warnings. >> B. Adding real initialization during gimplification, marking them = with =E2=80=9Cartificial_init=E2=80=9D.=20 >> Adjusting uninitialized pass, maintaining the annotation, making = sure the real init not >> Deleted from the fake init.=20 >> C. Marking the DECL for an uninitialized auto variable as = =E2=80=9Cno_explicit_init=E2=80=9D during gimplification, >> maintain this =E2=80=9Cno_explicit_init=E2=80=9D bit till after = pass_late_warn_uninitialized, or till pass_expand,=20 >> add real initialization for all DECLs that are marked with = =E2=80=9Cno_explicit_init=E2=80=9D. >> D. Adding .DEFFERED_INIT during gimplification, expand the = .DEFFERED_INIT during expand to >> real initialization. Adjusting uninitialized pass with the new = refs with =E2=80=9C.DEFFERED_INIT=E2=80=9D. >>=20 >>=20 >> In the above, approach A will be the one that have the minimum = run-time cost, will be the base for the performance >> comparison.=20 >>=20 >> I will implement approach D then, this one is expected to have the = most run-time overhead among the above list, but >> Implementation should be the cleanest among B, C, D. Let=E2=80=99s = see how much more performance overhead this approach >> will be. If the data is good, maybe we can avoid the effort to = implement B, and C.=20 >>=20 >> If the performance of D is not good, I will implement B or C at that = time. >>=20 >> Let me know if you have any comment or suggestions. >>=20 >> Thanks. >>=20 >> Qing >=20