From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (qmail 123312 invoked by alias); 8 Nov 2019 17:41:27 -0000 Mailing-List: contact elfutils-devel-help@sourceware.org; run by ezmlm Precedence: bulk List-Id: List-Post: List-Help: List-Subscribe: Sender: elfutils-devel-owner@sourceware.org Received: (qmail 123302 invoked by uid 89); 8 Nov 2019 17:41:27 -0000 Authentication-Results: sourceware.org; auth=none X-Virus-Checked: by ClamAV 0.100.3 on sourceware.org X-Virus-Found: No X-Spam-SWARE-Status: No, score=-10.6 required=5.0 tests=AWL,BAYES_00,HTML_MESSAGE,RCVD_IN_DNSWL_LOW,SPF_PASS autolearn=ham version=3.3.1 spammy=H*c:alternative X-Spam-Status: No, score=-10.6 required=5.0 tests=AWL,BAYES_00,HTML_MESSAGE,RCVD_IN_DNSWL_LOW,SPF_PASS autolearn=ham version=3.3.1 X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on sourceware.org X-Spam-Level: X-HELO: mx0a-0010f301.pphosted.com Received: from mx0a-0010f301.pphosted.com (HELO mx0a-0010f301.pphosted.com) (148.163.149.254) by sourceware.org (qpsmtpd/0.93/v0.84-503-g423c35a) with ESMTP; Fri, 08 Nov 2019 17:41:25 +0000 Received: from pps.filterd (m0102855.ppops.net [127.0.0.1]) by mx0b-0010f301.pphosted.com (8.16.0.42/8.16.0.42) with SMTP id xA8HaH0T007759; Fri, 8 Nov 2019 11:41:21 -0600 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=rice.edu; h=date : from : subject : to : cc : message-id : in-reply-to : references : mime-version : content-type; s=ricemail; bh=T4v+wEVU6rT0O3MSip6eQyLVTyc7hNfh2OtsVDYaF3I=; b=oCNtluWLWDzWUZ2jQn1Xa2VQ897pqKnDEcd39VnG2033VFSSDxf2DXNDlUls2gLYOUC7 5Ad+1XSmzcdQWf5uN4UlsOSwTpqzS+DcPpVkUxkx7cVOvwlg6elENYmm+9OBd8g2YfZG 4/ccerGPVrxG0XFGInMb69u7hb8S16STgemQQj2XpPLl5mzquoBc8KXtCobex2HqXDID FugjVmVauahoikJi9JVaEmhtAQpuuIGJW8QeqHFsOXyo/gdAlH0kaloDAldTUfOvEkHT kXVMsihfe/9sWt3IC3Gq43GqRgCjsspoTI0RChQ4YuH7ei6j7snEnjXMDSRIRzEM3fxH zQ== Received: from mh1.mail.rice.edu (mh1.mail.rice.edu [128.42.201.20]) by mx0b-0010f301.pphosted.com with ESMTP id 2w41umb5j3-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Fri, 08 Nov 2019 11:41:21 -0600 Received-X: from mh1.mail.rice.edu (localhost.localdomain [127.0.0.1]) by mh1.mail.rice.edu (Postfix) with ESMTP id 7D2E8460E9C; Fri, 8 Nov 2019 11:41:20 -0600 (CST) Received-X: from mh1.mail.rice.edu (localhost.localdomain [127.0.0.1]) by mh1.mail.rice.edu (Postfix) with ESMTP id 7BD63460E8B; Fri, 8 Nov 2019 11:41:20 -0600 (CST) X-Virus-Scanned: by amavis-2.7.0 at mh1.mail.rice.edu, auth channel Received-X: from mh1.mail.rice.edu ([127.0.0.1]) by mh1.mail.rice.edu (mh1.mail.rice.edu [127.0.0.1]) (amavis, port 10026) with ESMTP id bjqAureCldJt; Fri, 8 Nov 2019 11:41:20 -0600 (CST) Received: from cslinux29.cs.rice.edu (cslinux29.cs.rice.edu [168.7.116.104]) (using TLSv1.2 with cipher AES256-SHA (256/256 bits)) (No client certificate requested) (Authenticated sender: jma14) by mh1.mail.rice.edu (Postfix) with ESMTPSA id 4CD30460E8A; Fri, 8 Nov 2019 11:41:20 -0600 (CST) Date: Fri, 08 Nov 2019 17:41:00 -0000 From: Jonathon Anderson Subject: Re: [PATCH 2/2] libdw: Rewrite the memory handler to be more robust. To: Mark Wielaard Cc: elfutils-devel@sourceware.org Message-Id: <1573234880.2134.2@rice.edu> In-Reply-To: <9caa7eee4a810e3f26cb2cb4ec4046e15d7dad4e.camel@klomp.org> References: <1572380520.19948.0@rice.edu> <20191029211437.3268-1-mark@klomp.org> <20191029211437.3268-2-mark@klomp.org> <93a4d8983b6ec43c09c6c3b3f6ed8d358321bb9d.camel@klomp.org> <1573152030.2173.2@rice.edu> <9caa7eee4a810e3f26cb2cb4ec4046e15d7dad4e.camel@klomp.org> X-Mailer: geary/3.34.1 MIME-Version: 1.0 X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10434:6.0.95,18.0.572 definitions=2019-11-08_06:2019-11-08,2019-11-08 signatures=0 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=8 lowpriorityscore=0 clxscore=1015 mlxscore=8 priorityscore=1501 adultscore=0 spamscore=8 bulkscore=0 suspectscore=0 mlxlogscore=107 phishscore=0 impostorscore=0 malwarescore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-1910280000 definitions=main-1911080173 Content-Type: text/plain; charset=us-ascii; format=flowed X-SW-Source: 2019-q4/txt/msg00118.txt.bz2 On Fri, Nov 8, 2019 at 17:22, Mark Wielaard wrote: > On Thu, 2019-11-07 at 12:40 -0600, Jonathon Anderson wrote: >> I haven't benchmarked this version, but I did benchmark the >> equivalent >> earlier version (this version is almost quite literally a rebase of >> the >> other). I don't have the exact results on hand, what I remember is >> that >> the pthread_key method was faster (and handled the many-thread case >> better), by maybe a factor of 1.5x-2x in parallel. In serial the >> overhead was minimal (just an extra pointer indirection on >> allocations). > > I just tested the single-threaded case a bit and is not measurable > slower than the previous version, and compared to 0.177 things are > maybe ~1% slower (so probably in the noise). > > A factor 1.5x-2.0x slower in parallel does seem significant. Is that > in > the case of many-threads that are colliding a lot or in general? I believe it was 64 threads colliding a lot (on the reader side of mem_rwl). That said, this is all based on my memory from before the semester started. (They may also be numbers munged out of a larger benchmark, so don't trust them too much). As it happens, on our end any slowdown is entirely hidden by all the other work we do while reading DIEs, so its not a critical concern. Our code opens a Dwarf and then uses a #pragma parallel for across the CUs (using a serial recursion to read the DIEs), if you want to benchmark it that should suffice on a large enough example. > > Thanks, > > Mark