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 Received: from lists.gnu.org (lists.gnu.org [209.51.188.17]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 8A998C43334 for ; Fri, 22 Jul 2022 08:36:01 +0000 (UTC) Received: from localhost ([::1]:39382 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1oEo8e-0002EV-6e for qemu-devel@archiver.kernel.org; Fri, 22 Jul 2022 04:36:00 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:39754) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1oEo37-0000RT-0W for qemu-devel@nongnu.org; Fri, 22 Jul 2022 04:30:21 -0400 Received: from us-smtp-delivery-124.mimecast.com ([170.10.129.124]:35016) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1oEo2z-0007lf-7t for qemu-devel@nongnu.org; Fri, 22 Jul 2022 04:30:14 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1658478608; h=from:from:reply-to:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:cc:mime-version:mime-version: content-type:content-type:in-reply-to:in-reply-to: references:references; bh=AvWO1sCNT/zhIxqHtNDiqYhLV4XpMJbrSEwCA5NBPrk=; b=Zf7ZGde58YCTUDmsWquUaehj3ja7oC55aFPQs7+3SqA8sI3SIIELwPEaAux410oxL9HATo b/fXBswGHzG6KwINrBEjhOV02bCZdTgJHo8out8G8XSAnyTE/w7s1YB6oJUKKVws4esCBf er19syOzSeed1/MdO57q1vg+8RVLHH4= Received: from mimecast-mx02.redhat.com (mx3-rdu2.redhat.com [66.187.233.73]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id us-mta-215-E0A-gGScMjSKrn0amf1PJA-1; Fri, 22 Jul 2022 04:30:04 -0400 X-MC-Unique: E0A-gGScMjSKrn0amf1PJA-1 Received: from smtp.corp.redhat.com (int-mx07.intmail.prod.int.rdu2.redhat.com [10.11.54.7]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx02.redhat.com (Postfix) with ESMTPS id 71D782812C22; Fri, 22 Jul 2022 08:30:04 +0000 (UTC) Received: from redhat.com (unknown [10.33.36.91]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 57E261410F3C; Fri, 22 Jul 2022 08:30:03 +0000 (UTC) Date: Fri, 22 Jul 2022 09:29:58 +0100 From: Daniel =?utf-8?B?UC4gQmVycmFuZ8Op?= To: "Zhao, Zhou" Cc: "Xu, Ling1" , "qemu-devel@nongnu.org" , "quintela@redhat.com" , "dgilbert@redhat.com" , "Jin, Jun I" Subject: Re: [PATCH 1/1] Add AVX512 support for xbzrle_encode_buffer function Message-ID: References: <20220721103147.96608-1-ling1.xu@intel.com> <20220721103147.96608-2-ling1.xu@intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: User-Agent: Mutt/2.2.6 (2022-06-05) X-Scanned-By: MIMEDefang 2.85 on 10.11.54.7 Received-SPF: pass client-ip=170.10.129.124; envelope-from=berrange@redhat.com; helo=us-smtp-delivery-124.mimecast.com X-Spam_score_int: -23 X-Spam_score: -2.4 X-Spam_bar: -- X-Spam_report: (-2.4 / 5.0 requ) BAYES_00=-1.9, DKIM_INVALID=0.1, DKIM_SIGNED=0.1, RCVD_IN_DNSWL_LOW=-0.7, SPF_HELO_NONE=0.001, SPF_PASS=-0.001, T_SCC_BODY_TEXT_LINE=-0.01 autolearn=ham autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Reply-To: Daniel =?utf-8?B?UC4gQmVycmFuZ8Op?= Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" On Fri, Jul 22, 2022 at 02:23:13AM +0000, Zhao, Zhou wrote: > 1 we need gcc machined options to tirgger gcc enable SIMD > instructions(https://gcc.gnu.org/onlinedocs/gcc/x86-Options.html). > Or it will trigger a compile error. This is the reason why we > change the config file. Take a look at util/bufferiszero.c - that uses '#pragma GCC target' to selectively change the compule target of individual functions. This is what is njeeded here, because most distros are going to compile QEMU with a very old x86_64 baseline, never turn on avx512 for the whole QEMU build. It needs to be very selective to make it usable for typical deployments. With regards, Daniel -- |: https://berrange.com -o- https://www.flickr.com/photos/dberrange :| |: https://libvirt.org -o- https://fstop138.berrange.com :| |: https://entangle-photo.org -o- https://www.instagram.com/dberrange :|