From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mx2.suse.de (mx2.suse.de [195.135.220.15]) by sourceware.org (Postfix) with ESMTPS id E117D386F008 for ; Tue, 29 Sep 2020 18:19:04 +0000 (GMT) DMARC-Filter: OpenDMARC Filter v1.3.2 sourceware.org E117D386F008 Authentication-Results: sourceware.org; dmarc=none (p=none dis=none) header.from=suse.cz Authentication-Results: sourceware.org; spf=pass smtp.mailfrom=mjambor@suse.cz X-Virus-Scanned: by amavisd-new at test-mx.suse.de Received: from relay2.suse.de (unknown [195.135.221.27]) by mx2.suse.de (Postfix) with ESMTP id F15DCB209 for ; Tue, 29 Sep 2020 18:19:02 +0000 (UTC) Resent-From: Martin Jambor Resent-Date: Tue, 29 Sep 2020 20:19:02 +0200 Resent-Message-ID: <20200929181902.GG13380@virgil.suse.cz> Resent-To: GCC Patches Message-Id: <5361cc8dc62a8199ab1db6cdeac4f5fc1114bcc2.1601403165.git.mjambor@suse.cz> In-Reply-To: References: From: Martin Jambor Date: Mon, 21 Sep 2020 16:25:18 +0200 Subject: [PATCH 6/6] ipa-cp: Separate and increase the large-unit parameter To: GCC Patches Cc: Jan Hubicka X-Spam-Status: No, score=-3038.0 required=5.0 tests=BAYES_00, GIT_PATCH_0, KAM_DMARC_STATUS, RCVD_IN_MSPIKE_H3, RCVD_IN_MSPIKE_WL, SPF_HELO_NONE, SPF_PASS, TXREP 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, 29 Sep 2020 18:19:06 -0000 A previous patch in the series has taught IPA-CP to identify the important cloning opportunities in 548.exchange2_r as worthwhile on their own, but the optimization is still prevented from taking place because of the overall unit-growh limit. This patches raises that limit so that it takes place and the benchmark runs 30% faster (on AMD Zen2 CPU at least). Before this patch, IPA-CP uses the following formulae to arrive at the overall_size limit: base = MAX(orig_size, param_large_unit_insns) unit_growth_limit = base + base * param_ipa_cp_unit_growth / 100 since param_ipa_cp_unit_growth has default 10, param_large_unit_insns has default value 10000. The problem with exchange2 (at least on zen2 but I have had a quick look on aarch64 too) is that the original estimated unit size is 10513 and so param_large_unit_insns does not apply and the default limit is therefore 11564 which is good enough only for one of the ideal 8 clonings, we need the limit to be at least 16291. I would like to raise param_ipa_cp_unit_growth a little bit more soon too, but most certainly not to 55. Therefore, the large_unit must be increased. In this patch, I decided to decouple the inlining and ipa-cp large-unit parameters. It also makes sense because IPA-CP uses it only at -O3 while inlining also at -O2 (IIUC). But if we agree we can try raising param_large_unit_insns to 13-14 thousand "instructions," perhaps it is not necessary. But then again, it may make sense to actually increase the IPA-CP limit further. I plan to experiment with IPA-CP tuning on a larger set of programs. Meanwhile, mainly to address the 548.exchange2_r regression, I'm suggesting this simple change. gcc/ChangeLog: 2020-09-07 Martin Jambor * params.opt (ipa-cp-large-unit-insns): New parameter. * ipa-cp.c (get_max_overall_size): Use the new parameter. --- gcc/ipa-cp.c | 2 +- gcc/params.opt | 4 ++++ 2 files changed, 5 insertions(+), 1 deletion(-) diff --git a/gcc/ipa-cp.c b/gcc/ipa-cp.c index 12acf24c553..2152f9e5876 100644 --- a/gcc/ipa-cp.c +++ b/gcc/ipa-cp.c @@ -3448,7 +3448,7 @@ static long get_max_overall_size (cgraph_node *node) { long max_new_size = orig_overall_size; - long large_unit = opt_for_fn (node->decl, param_large_unit_insns); + long large_unit = opt_for_fn (node->decl, param_ipa_cp_large_unit_insns); if (max_new_size < large_unit) max_new_size = large_unit; int unit_growth = opt_for_fn (node->decl, param_ipa_cp_unit_growth); diff --git a/gcc/params.opt b/gcc/params.opt index acb59f17e45..9d177ab50ad 100644 --- a/gcc/params.opt +++ b/gcc/params.opt @@ -218,6 +218,10 @@ Percentage penalty functions containing a single call to another function will r Common Joined UInteger Var(param_ipa_cp_unit_growth) Init(10) Param Optimization How much can given compilation unit grow because of the interprocedural constant propagation (in percent). +-param=ipa-cp-large-unit-insns= +Common Joined UInteger Var(param_ipa_cp_large_unit_insns) Optimization Init(16000) Param +The size of translation unit that IPA-CP pass considers large. + -param=ipa-cp-value-list-size= Common Joined UInteger Var(param_ipa_cp_value_list_size) Init(8) Param Optimization Maximum size of a list of values associated with each parameter for interprocedural constant propagation. -- 2.28.0