From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-vs1-xe2d.google.com (mail-vs1-xe2d.google.com [IPv6:2607:f8b0:4864:20::e2d]) by sourceware.org (Postfix) with ESMTPS id EE16A3858D28; Thu, 28 Apr 2022 00:15:40 +0000 (GMT) DMARC-Filter: OpenDMARC Filter v1.4.1 sourceware.org EE16A3858D28 Received: by mail-vs1-xe2d.google.com with SMTP id w124so3190224vsb.8; Wed, 27 Apr 2022 17:15:40 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc; bh=fHWUnO6rlk21YPSS6qH5hjFHLKdnd+1nExft/6q3rnM=; b=HOtlRvsRJbsVftVLYCTYA/y50zzfKWvLf9ajxLr21mdtt3kCUmMt2roGYOWc7qJLyl OdnbDUcIZOP2ZDbvm0vDpjJ572o1UA7NxpUCIt3FxP22ZRp/SiEcd6e2uTWQ13px+DYU vXG+GxymvE/cSBV960xwFjaBRjR8ojaiMVW+/IDQGue1haLDlr181InfUXrpdCDkn8J6 Cj9kBzxFr5ZQozP+O1Nmv1g2J5txE0Sr0LrxtZSOlhpC8BrGX0qXByoSRjOQhcI1lgtf 5/HeTOdrIkjRhw6ZgCrapKVepLkPQ3tmIrH2hFCMN7BSwfSAH4/9KFbyXkg0ttvE5uMA Epaw== X-Gm-Message-State: AOAM533g5PHVJ/uDs4vivRvlfnFav8DvV8cq+TJqGrBzK5LhHuIRlwsT KtG93pw36UTqruxLrB5BY1TAdaDf7He4pnGeeck= X-Google-Smtp-Source: ABdhPJx24byTvsZZ3MrjOf73dzqcOG7Enmvt4RmL+3CoTyDrLH/QtgZvMI8Zw/RUIs6HVTzegEs0NKaF33bTw8K4J+E= X-Received: by 2002:a05:6102:e0f:b0:32c:c002:3ca3 with SMTP id o15-20020a0561020e0f00b0032cc0023ca3mr6386092vst.28.1651104940276; Wed, 27 Apr 2022 17:15:40 -0700 (PDT) MIME-Version: 1.0 References: <20210726120055.1089971-1-hjl.tools@gmail.com> In-Reply-To: From: Sunil Pandey Date: Wed, 27 Apr 2022 17:15:03 -0700 Message-ID: Subject: Re: [PATCH] x86-64: Add Avoid_Short_Distance_REP_MOVSB To: Noah Goldstein , libc-stable@sourceware.org Cc: Alexey Tourbin , GNU C Library Content-Type: text/plain; charset="UTF-8" X-Spam-Status: No, score=-1.2 required=5.0 tests=BAYES_00, DKIM_SIGNED, DKIM_VALID, DKIM_VALID_AU, DKIM_VALID_EF, FREEMAIL_ENVFROM_END_DIGIT, FREEMAIL_FROM, HK_RANDOM_ENVFROM, HK_RANDOM_FROM, RCVD_IN_DNSWL_NONE, SPF_HELO_NONE, SPF_PASS, TXREP autolearn=no autolearn_force=no version=3.4.4 X-Spam-Checker-Version: SpamAssassin 3.4.4 (2020-01-24) on server2.sourceware.org X-BeenThere: libc-stable@sourceware.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Libc-stable mailing list List-Unsubscribe: , List-Archive: List-Help: List-Subscribe: , X-List-Received-Date: Thu, 28 Apr 2022 00:15:43 -0000 On Fri, Aug 27, 2021 at 7:58 PM Noah Goldstein via Libc-alpha wrote: > > On Fri, Aug 27, 2021 at 8:28 PM Alexey Tourbin via Libc-alpha < > libc-alpha@sourceware.org> wrote: > > > On Mon, Jul 26, 2021 at 3:03 PM H.J. Lu via Libc-alpha > > wrote: > > > --- a/sysdeps/x86_64/multiarch/memmove-vec-unaligned-erms.S > > > +++ b/sysdeps/x86_64/multiarch/memmove-vec-unaligned-erms.S > > > @@ -325,12 +325,16 @@ L(movsb): > > > /* Avoid slow backward REP MOVSB. */ > > > jb L(more_8x_vec_backward) > > > # if AVOID_SHORT_DISTANCE_REP_MOVSB > > > + andl $X86_STRING_CONTROL_AVOID_SHORT_DISTANCE_REP_MOVSB, > > __x86_string_control(%rip) > > > + jz 3f > > > movq %rdi, %rcx > > > subq %rsi, %rcx > > > jmp 2f > > > # endif > > > 1: > > > # if AVOID_SHORT_DISTANCE_REP_MOVSB > > > + andl $X86_STRING_CONTROL_AVOID_SHORT_DISTANCE_REP_MOVSB, > > __x86_string_control(%rip) > > > + jz 3f > > > movq %rsi, %rcx > > > subq %rdi, %rcx > > > 2: > > > > Why "andl" rather than "testl"? > > > > +1. I missed that before. > > My patches: [PATCH 5/5] X86-64: Optimize memmove-vec-unaligned-erms.S > > uses `testl` instead. Although my patch might not be checked in (and it may > be a > while) as we are still looking into the causes of the slowdown. I would like to backport this patch to release branches. Any comments or objections? --Sunil