From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from aserp2130.oracle.com (aserp2130.oracle.com [141.146.126.79]) by sourceware.org (Postfix) with ESMTPS id 37439384C003 for ; Wed, 13 Jan 2021 15:06:56 +0000 (GMT) DMARC-Filter: OpenDMARC Filter v1.3.2 sourceware.org 37439384C003 Received: from pps.filterd (aserp2130.oracle.com [127.0.0.1]) by aserp2130.oracle.com (8.16.0.42/8.16.0.42) with SMTP id 10DExdpl189327; Wed, 13 Jan 2021 15:06:51 GMT Received: from userp3020.oracle.com (userp3020.oracle.com [156.151.31.79]) by aserp2130.oracle.com with ESMTP id 360kg1ux3h-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Wed, 13 Jan 2021 15:06:50 +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 10DF0bgF010038; Wed, 13 Jan 2021 15:06:50 GMT Received: from userv0121.oracle.com (userv0121.oracle.com [156.151.31.72]) by userp3020.oracle.com with ESMTP id 360kf7r904-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Wed, 13 Jan 2021 15:06:49 +0000 Received: from abhmp0010.oracle.com (abhmp0010.oracle.com [141.146.116.16]) by userv0121.oracle.com (8.14.4/8.13.8) with ESMTP id 10DF6mCJ011023; Wed, 13 Jan 2021 15:06:48 GMT Received: from dhcp-10-39-222-121.vpn.oracle.com (/10.39.222.121) by default (Oracle Beehive Gateway v4.0) with ESMTP ; Wed, 13 Jan 2021 07:06:47 -0800 From: Qing Zhao Message-Id: <2C0218A8-0D9F-4C49-8293-EF0D19E00288@ORACLE.COM> 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 Date: Wed, 13 Jan 2021 09:06:46 -0600 In-Reply-To: Cc: Richard Sandiford , Richard Biener via Gcc-patches To: Richard Biener 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> 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-2101130094 X-Proofpoint-Virus-Version: vendor=nai engine=6000 definitions=9862 signatures=668683 X-Proofpoint-Spam-Details: rule=notspam policy=default score=0 malwarescore=0 suspectscore=0 clxscore=1015 impostorscore=0 spamscore=0 priorityscore=1501 mlxscore=0 phishscore=0 mlxlogscore=999 bulkscore=0 adultscore=0 lowpriorityscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2009150000 definitions=main-2101130094 X-Spam-Status: No, score=-4.0 required=5.0 tests=BAYES_00, DKIMWL_WL_HIGH, DKIM_SIGNED, DKIM_VALID, DKIM_VALID_AU, DKIM_VALID_EF, HTML_MESSAGE, 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 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable X-Content-Filtered-By: Mailman/MimeDel 2.1.29 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: Wed, 13 Jan 2021 15:07:06 -0000 > On Jan 13, 2021, at 1:39 AM, Richard Biener wrote: >=20 > On Tue, 12 Jan 2021, Qing Zhao wrote: >=20 >> Hi,=20 >>=20 >> Just check in to see whether you have any comments and suggestions on = this: >>=20 >> FYI, I have been continue with Approach D implementation since last = week: >>=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 >> For the remaining work of Approach D: >>=20 >> ** complete the implementation of -ftrivial-auto-var-init=3Dpattern; >> ** complete the implementation of uninitialized warnings maintenance = work for D.=20 >>=20 >> I have completed the uninitialized warnings maintenance work for D. >> And finished partial of the -ftrivial-auto-var-init=3Dpattern = implementation.=20 >>=20 >> The following are remaining work of Approach D: >>=20 >> ** -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 >>=20 >> Please let me know if you have any objection on my current decision = on implementing approach D.=20 >=20 > Did you do any analysis on how stack usage and code size are changed=20= > with approach D? I did the code size change comparison (I will provide the data in = another email). And with this data, D works better than A in general. = (This is surprise to me actually). But not the stack usage. Not sure how to collect the stack usage data, = do you have any suggestion on this? > How does compile-time behave (we could gobble up > lots of .DEFERRED_INIT calls I guess)? I can collect this data too and report it later. Thanks. Qing >=20 > Richard. >=20 >> Thanks a lot for your help. >>=20 >> Qing >>=20 >>=20 >>> 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 >>=20 >>=20 >=20 > --=20 > Richard Biener > > SUSE Software Solutions Germany GmbH, Maxfeldstrasse 5, 90409 = Nuernberg, > Germany; GF: Felix Imend=C3=B6rffer; HRB 36809 (AG Nuernberg)