From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-11.1 required=3.0 tests=BAYES_00,DKIM_INVALID, DKIM_SIGNED,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI, NICE_REPLY_A,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED, USER_AGENT_SANE_1 autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 26A2EC43461 for ; Thu, 17 Sep 2020 14:39:49 +0000 (UTC) Received: from lists.ozlabs.org (lists.ozlabs.org [203.11.71.2]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 459042223C for ; Thu, 17 Sep 2020 14:39:48 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (2048-bit key) header.d=ibm.com header.i=@ibm.com header.b="mcq8EvZa" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 459042223C Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=linux.ibm.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=linuxppc-dev-bounces+linuxppc-dev=archiver.kernel.org@lists.ozlabs.org Received: from bilbo.ozlabs.org (lists.ozlabs.org [IPv6:2401:3900:2:1::3]) by lists.ozlabs.org (Postfix) with ESMTP id 4BsfkV29WVzDqfW for ; Fri, 18 Sep 2020 00:39:46 +1000 (AEST) Received: from ozlabs.org (bilbo.ozlabs.org [203.11.71.1]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits) server-digest SHA256) (No client certificate requested) by lists.ozlabs.org (Postfix) with ESMTPS id 4Bsfck1nXjzDqdP for ; Fri, 18 Sep 2020 00:34:46 +1000 (AEST) Authentication-Results: lists.ozlabs.org; dmarc=pass (p=none dis=none) header.from=linux.ibm.com Authentication-Results: lists.ozlabs.org; dkim=pass (2048-bit key; unprotected) header.d=ibm.com header.i=@ibm.com header.a=rsa-sha256 header.s=pp1 header.b=mcq8EvZa; dkim-atps=neutral Received: from ozlabs.org (bilbo.ozlabs.org [IPv6:2401:3900:2:1::2]) by bilbo.ozlabs.org (Postfix) with ESMTP id 4Bsfcg6dXnz8tDb for ; Fri, 18 Sep 2020 00:34:43 +1000 (AEST) Received: by ozlabs.org (Postfix) id 4Bsfcg39B0z9sTQ; Fri, 18 Sep 2020 00:34:43 +1000 (AEST) Authentication-Results: ozlabs.org; spf=pass (sender SPF authorized) smtp.mailfrom=linux.ibm.com (client-ip=148.163.158.5; helo=mx0a-001b2d01.pphosted.com; envelope-from=ldufour@linux.ibm.com; receiver=) Authentication-Results: ozlabs.org; dmarc=pass (p=none dis=none) header.from=linux.ibm.com Authentication-Results: ozlabs.org; dkim=pass (2048-bit key; unprotected) header.d=ibm.com header.i=@ibm.com header.a=rsa-sha256 header.s=pp1 header.b=mcq8EvZa; dkim-atps=neutral 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 ozlabs.org (Postfix) with ESMTPS id 4Bsfcf4Rwxz9sSC for ; Fri, 18 Sep 2020 00:34:42 +1000 (AEST) Received: from pps.filterd (m0098419.ppops.net [127.0.0.1]) by mx0b-001b2d01.pphosted.com (8.16.0.42/8.16.0.42) with SMTP id 08HEVCIF070270; Thu, 17 Sep 2020 10:34:39 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=ibm.com; h=subject : to : cc : references : from : message-id : date : mime-version : in-reply-to : content-type : content-transfer-encoding; s=pp1; bh=5PweI626aVqvd04/PHyDOiFrDPfBB35SaFBtl0ALKFE=; b=mcq8EvZa5m2sFZgP6KTUVP7wShssiI3O/Ap67JjaZdsTDtpFyV6lih6LYhEHEEetKfXp ZMXX7buWFDMZHigr2Dc4+gOwPRFXUSLOkij4ORO2i+yHmcGahyytY6kiSNFuuyDo/8Bv Q8EHtYJhNg9sR9rFCOYjMMnc9uNFF1c5NYM2BNr2WuLqBG8QAQshBIzJI6CC3BmXy00D LuUVQ4HZi3jKihmgUSiKqXR9E8v0c0/Qf/UqSXpDc31x/ekMnY4+6ncSWzh1f5YusXOO GdI2VaZUjTB8Qwlld4v0AHsjEWM3sg3YBpOfdzI0Sb5/roW4Nn/yWfNWcgQI1i/IAJVl QQ== Received: from pps.reinject (localhost [127.0.0.1]) by mx0b-001b2d01.pphosted.com with ESMTP id 33m7kb4xmj-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Thu, 17 Sep 2020 10:34:39 -0400 Received: from m0098419.ppops.net (m0098419.ppops.net [127.0.0.1]) by pps.reinject (8.16.0.36/8.16.0.36) with SMTP id 08HEW5qx073866; Thu, 17 Sep 2020 10:34:38 -0400 Received: from ppma03ams.nl.ibm.com (62.31.33a9.ip4.static.sl-reverse.com [169.51.49.98]) by mx0b-001b2d01.pphosted.com with ESMTP id 33m7kb4xkp-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Thu, 17 Sep 2020 10:34:38 -0400 Received: from pps.filterd (ppma03ams.nl.ibm.com [127.0.0.1]) by ppma03ams.nl.ibm.com (8.16.0.42/8.16.0.42) with SMTP id 08HEXtE2022046; Thu, 17 Sep 2020 14:34:37 GMT Received: from b06cxnps4076.portsmouth.uk.ibm.com (d06relay13.portsmouth.uk.ibm.com [9.149.109.198]) by ppma03ams.nl.ibm.com with ESMTP id 33k6esj70f-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Thu, 17 Sep 2020 14:34:36 +0000 Received: from b06wcsmtp001.portsmouth.uk.ibm.com (b06wcsmtp001.portsmouth.uk.ibm.com [9.149.105.160]) by b06cxnps4076.portsmouth.uk.ibm.com (8.14.9/8.14.9/NCO v10.0) with ESMTP id 08HEYXXK22872544 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Thu, 17 Sep 2020 14:34:34 GMT Received: from b06wcsmtp001.portsmouth.uk.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id DEF81A405F; Thu, 17 Sep 2020 14:34:33 +0000 (GMT) Received: from b06wcsmtp001.portsmouth.uk.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id 90F36A405B; Thu, 17 Sep 2020 14:34:33 +0000 (GMT) Received: from pomme.local (unknown [9.145.31.89]) by b06wcsmtp001.portsmouth.uk.ibm.com (Postfix) with ESMTP; Thu, 17 Sep 2020 14:34:33 +0000 (GMT) Subject: Re: [PATCH v4] pseries/hotplug-memory: hot-add: skip redundant LMB lookup To: Scott Cheloha , linuxppc-dev@ozlabs.org References: <20200916145122.3408129-1-cheloha@linux.ibm.com> From: Laurent Dufour Message-ID: <992d87d2-1505-aab6-c6f7-c11a56d45235@linux.ibm.com> Date: Thu, 17 Sep 2020 16:34:33 +0200 User-Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.15; rv:68.0) Gecko/20100101 Thunderbird/68.12.0 MIME-Version: 1.0 In-Reply-To: <20200916145122.3408129-1-cheloha@linux.ibm.com> Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-US Content-Transfer-Encoding: 8bit X-TM-AS-GCONF: 00 X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10434:6.0.235, 18.0.687 definitions=2020-09-17_09:2020-09-16, 2020-09-17 signatures=0 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 lowpriorityscore=0 malwarescore=0 impostorscore=0 priorityscore=1501 mlxscore=0 adultscore=0 mlxlogscore=999 clxscore=1011 phishscore=0 spamscore=0 bulkscore=0 suspectscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2006250000 definitions=main-2009170109 X-BeenThere: linuxppc-dev@lists.ozlabs.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Nathan Lynch , Michal Suchanek , David Hildenbrand , Rick Lindsley Errors-To: linuxppc-dev-bounces+linuxppc-dev=archiver.kernel.org@lists.ozlabs.org Sender: "Linuxppc-dev" Le 16/09/2020 à 16:51, Scott Cheloha a écrit : > During memory hot-add, dlpar_add_lmb() calls memory_add_physaddr_to_nid() > to determine which node id (nid) to use when later calling __add_memory(). > > This is wasteful. On pseries, memory_add_physaddr_to_nid() finds an > appropriate nid for a given address by looking up the LMB containing the > address and then passing that LMB to of_drconf_to_nid_single() to get the > nid. In dlpar_add_lmb() we get this address from the LMB itself. > > In short, we have a pointer to an LMB and then we are searching for > that LMB *again* in order to find its nid. > > If we call of_drconf_to_nid_single() directly from dlpar_add_lmb() we > can skip the redundant lookup. The only error handling we need to > duplicate from memory_add_physaddr_to_nid() is the fallback to the > default nid when drconf_to_nid_single() returns -1 (NUMA_NO_NODE) or > an invalid nid. > > Skipping the extra lookup makes hot-add operations faster, especially > on machines with many LMBs. > > Consider an LPAR with 126976 LMBs. In one test, hot-adding 126000 > LMBs on an upatched kernel took ~3.5 hours while a patched kernel > completed the same operation in ~2 hours: > > Unpatched (12450 seconds): > Sep 9 04:06:31 ltc-brazos1 drmgr[810169]: drmgr: -c mem -a -q 126000 > Sep 9 04:06:31 ltc-brazos1 kernel: pseries-hotplug-mem: Attempting to hot-add 126000 LMB(s) > [...] > Sep 9 07:34:01 ltc-brazos1 kernel: pseries-hotplug-mem: Memory at 20000000 (drc index 80000002) was hot-added > > Patched (7065 seconds): > Sep 8 21:49:57 ltc-brazos1 drmgr[877703]: drmgr: -c mem -a -q 126000 > Sep 8 21:49:57 ltc-brazos1 kernel: pseries-hotplug-mem: Attempting to hot-add 126000 LMB(s) > [...] > Sep 8 23:27:42 ltc-brazos1 kernel: pseries-hotplug-mem: Memory at 20000000 (drc index 80000002) was hot-added > > It should be noted that the speedup grows more substantial when > hot-adding LMBs at the end of the drconf range. This is because we > are skipping a linear LMB search. > > To see the distinction, consider smaller hot-add test on the same > LPAR. A perf-stat run with 10 iterations showed that hot-adding 4096 > LMBs completed less than 1 second faster on a patched kernel: > > Unpatched: > Performance counter stats for 'drmgr -c mem -a -q 4096' (10 runs): > > 104,753.42 msec task-clock # 0.992 CPUs utilized ( +- 0.55% ) > 4,708 context-switches # 0.045 K/sec ( +- 0.69% ) > 2,444 cpu-migrations # 0.023 K/sec ( +- 1.25% ) > 394 page-faults # 0.004 K/sec ( +- 0.22% ) > 445,902,503,057 cycles # 4.257 GHz ( +- 0.55% ) (66.67%) > 8,558,376,740 stalled-cycles-frontend # 1.92% frontend cycles idle ( +- 0.88% ) (49.99%) > 300,346,181,651 stalled-cycles-backend # 67.36% backend cycles idle ( +- 0.76% ) (50.01%) > 258,091,488,691 instructions # 0.58 insn per cycle > # 1.16 stalled cycles per insn ( +- 0.22% ) (66.67%) > 70,568,169,256 branches # 673.660 M/sec ( +- 0.17% ) (50.01%) > 3,100,725,426 branch-misses # 4.39% of all branches ( +- 0.20% ) (49.99%) > > 105.583 +- 0.589 seconds time elapsed ( +- 0.56% ) > > Patched: > Performance counter stats for 'drmgr -c mem -a -q 4096' (10 runs): > > 104,055.69 msec task-clock # 0.993 CPUs utilized ( +- 0.32% ) > 4,606 context-switches # 0.044 K/sec ( +- 0.20% ) > 2,463 cpu-migrations # 0.024 K/sec ( +- 0.93% ) > 394 page-faults # 0.004 K/sec ( +- 0.25% ) > 442,951,129,921 cycles # 4.257 GHz ( +- 0.32% ) (66.66%) > 8,710,413,329 stalled-cycles-frontend # 1.97% frontend cycles idle ( +- 0.47% ) (50.06%) > 299,656,905,836 stalled-cycles-backend # 67.65% backend cycles idle ( +- 0.39% ) (50.02%) > 252,731,168,193 instructions # 0.57 insn per cycle > # 1.19 stalled cycles per insn ( +- 0.20% ) (66.66%) > 68,902,851,121 branches # 662.173 M/sec ( +- 0.13% ) (49.94%) > 3,100,242,882 branch-misses # 4.50% of all branches ( +- 0.15% ) (49.98%) > > 104.829 +- 0.325 seconds time elapsed ( +- 0.31% ) > > This is consistent. An add-by-count hot-add operation adds LMBs > greedily, so LMBs near the start of the drconf range are considered > first. On an otherwise idle LPAR with so many LMBs we would expect to > find the LMBs we need near the start of the drconf range, hence the > smaller speedup. > > Signed-off-by: Scott Cheloha Reviewed-by: Laurent Dufour > --- > Changelog: > > v1: https://lore.kernel.org/linuxppc-dev/20200910175637.2865160-1-cheloha@linux.ibm.com/ > > v2: > - Move prototype for of_drconf_to_nid_single() to topology.h. > Requested by Michael Ellerman. > > v3: > - Send the right patch. v2 is from the wrong branch, my mistake. > > v4: > - Fix checkpatch.pl warnings. Reported by Laurent Dufour. > > arch/powerpc/include/asm/topology.h | 3 +++ > arch/powerpc/mm/numa.c | 2 +- > arch/powerpc/platforms/pseries/hotplug-memory.c | 6 ++++-- > 3 files changed, 8 insertions(+), 3 deletions(-) > > diff --git a/arch/powerpc/include/asm/topology.h b/arch/powerpc/include/asm/topology.h > index f0b6300e7dd3..ae19b19f9d44 100644 > --- a/arch/powerpc/include/asm/topology.h > +++ b/arch/powerpc/include/asm/topology.h > @@ -86,6 +86,9 @@ static inline int cpu_distance(__be32 *cpu1_assoc, __be32 *cpu2_assoc) > > #endif /* CONFIG_NUMA */ > > +struct drmem_lmb; > +int of_drconf_to_nid_single(struct drmem_lmb *lmb); > + > #if defined(CONFIG_NUMA) && defined(CONFIG_PPC_SPLPAR) > extern int find_and_online_cpu_nid(int cpu); > #else > diff --git a/arch/powerpc/mm/numa.c b/arch/powerpc/mm/numa.c > index 1f61fa2148b5..63507b47164d 100644 > --- a/arch/powerpc/mm/numa.c > +++ b/arch/powerpc/mm/numa.c > @@ -430,7 +430,7 @@ static int of_get_assoc_arrays(struct assoc_arrays *aa) > * This is like of_node_to_nid_single() for memory represented in the > * ibm,dynamic-reconfiguration-memory node. > */ > -static int of_drconf_to_nid_single(struct drmem_lmb *lmb) > +int of_drconf_to_nid_single(struct drmem_lmb *lmb) > { > struct assoc_arrays aa = { .arrays = NULL }; > int default_nid = NUMA_NO_NODE; > diff --git a/arch/powerpc/platforms/pseries/hotplug-memory.c b/arch/powerpc/platforms/pseries/hotplug-memory.c > index 0ea976d1cac4..9a533acf8ad0 100644 > --- a/arch/powerpc/platforms/pseries/hotplug-memory.c > +++ b/arch/powerpc/platforms/pseries/hotplug-memory.c > @@ -611,8 +611,10 @@ static int dlpar_add_lmb(struct drmem_lmb *lmb) > > block_sz = memory_block_size_bytes(); > > - /* Find the node id for this address. */ > - nid = memory_add_physaddr_to_nid(lmb->base_addr); > + /* Find the node id for this LMB. Fake one if necessary. */ > + nid = of_drconf_to_nid_single(lmb); > + if (nid < 0 || !node_possible(nid)) > + nid = first_online_node; > > /* Add the memory */ > rc = __add_memory(nid, lmb->base_addr, block_sz); >