From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-pg1-x533.google.com (mail-pg1-x533.google.com [IPv6:2607:f8b0:4864:20::533]) by sourceware.org (Postfix) with ESMTPS id 8BC6D3890407 for ; Sat, 1 May 2021 18:45:59 +0000 (GMT) DMARC-Filter: OpenDMARC Filter v1.3.2 sourceware.org 8BC6D3890407 Received: by mail-pg1-x533.google.com with SMTP id m37so834927pgb.8 for ; Sat, 01 May 2021 11:45:59 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc; bh=L6IFlfUkSlLyjUhj4NkvgXQ+Si0pKn3ZLjU7Ak4bPQ8=; b=lvfZYTVBkeliv98THBie9pg8/oqKpiOsJLgOOJ6Mzjd4W4I7aV2M0TfY2nMjjy8vPU 7Om4JAYo3vl5sXiV6VwZUuyh/YC1xY86k56Nx8+03xm8kyxHfh8Frsi6kNxd95b2r3l6 Lkcrqoe3ra7zuOuMrqUmavp529zdPixNUgyh2Tl+Ee62QkvnDJ8PIWi84YTkLdXz8KZE TbWcpmrNYHy6yhW+XSNASZhfJglg7AK2CP7OpXkNNnchSbjnJ4fmBU6fwKLRk8qVB7yn LrNsi71lWeNjvDDW9B+Y2XeBJHCmLvLhX0PhR3/XPU/2/pHgqUFg8tddon/6+mgLtl5C uPXg== X-Gm-Message-State: AOAM5312A6npAvzXQBuEcd61sQEtRtpOnclbWJtVt0M093Lmbuc1IrjX DVVkm23KDfc25+a4OybqVKSz/m/y6ngv9ZxikfA= X-Google-Smtp-Source: ABdhPJxQgmhUxaMuEaScGjo7fms+wp+qqc2YmjRszjjMV4XRvcSbO+DIWrKnomtM4HR1N32kOE2XObjXy/caGzliOGA= X-Received: by 2002:a63:1c22:: with SMTP id c34mr10403249pgc.408.1619894758477; Sat, 01 May 2021 11:45:58 -0700 (PDT) MIME-Version: 1.0 References: <20210430182442.3612464-1-hjl.tools@gmail.com> In-Reply-To: From: Noah Goldstein Date: Sat, 1 May 2021 14:45:47 -0400 Message-ID: Subject: Re: [PATCH v2] x86: Set rep_movsb_threshold to 2112 on processors with FSRM To: "H.J. Lu" Cc: GNU C Library Content-Type: text/plain; charset="UTF-8" X-Spam-Status: No, score=-3.7 required=5.0 tests=BAYES_00, DKIM_SIGNED, DKIM_VALID, DKIM_VALID_AU, DKIM_VALID_EF, FREEMAIL_FROM, RCVD_IN_DNSWL_NONE, 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: libc-alpha@sourceware.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Libc-alpha mailing list List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Sat, 01 May 2021 18:46:01 -0000 On Sat, May 1, 2021 at 10:09 AM H.J. Lu wrote: > > On Fri, Apr 30, 2021 at 6:26 PM H.J. Lu wrote: > > > > On Fri, Apr 30, 2021 at 5:17 PM Noah Goldstein wrote: > > > > > > On Fri, Apr 30, 2021 at 4:51 PM H.J. Lu wrote: > > > > > > > > On Fri, Apr 30, 2021 at 3:59 PM Noah Goldstein wrote: > > > > > > > > > > On Fri, Apr 30, 2021 at 4:43 PM H.J. Lu via Libc-alpha > > > > > wrote: > > > > > > > > > > > > The glibc memcpy benchmark on Intel Core i7-1065G7 (Ice Lake) showed > > > > > > that REP MOVSB became faster after 2112 bytes: > > > > > > > > > > > > Vector + REP MOVSB REP MOVSB > > > > > > length=2112, align1=0, align2=0: 24.20 24.40 > > > > > > length=2112, align1=1, align2=0: 26.07 23.13 > > > > > > length=2112, align1=0, align2=1: 27.18 28.13 > > > > > > length=2112, align1=1, align2=1: 26.23 25.16 > > > > > > length=2176, align1=0, align2=0: 23.18 22.52 > > > > > > length=2176, align1=2, align2=0: 25.45 22.52 > > > > > > length=2176, align1=0, align2=2: 27.14 27.82 > > > > > > length=2176, align1=2, align2=2: 22.73 25.56 > > > > > > length=2240, align1=0, align2=0: 24.62 24.25 > > > > > > length=2240, align1=3, align2=0: 29.77 27.15 > > > > > > length=2240, align1=0, align2=3: 35.55 29.93 > > > > > > length=2240, align1=3, align2=3: 34.49 25.15 > > > > > > length=2304, align1=0, align2=0: 34.75 26.64 > > > > > > length=2304, align1=4, align2=0: 32.09 22.63 > > > > > > length=2304, align1=0, align2=4: 28.43 31.24 > > > > > > > > > > > > > > > > Do you know what is happening at: > > > > > length=2304, align1=0, align2=4: 28.43 31.24 > > > > > > > > > > Seems align2 > align1 gets worse for larger sizes as well. > > > > > > > > > > I.e from my Icelake (1 run): > > > > > w/o > > > > > Patch w/ Patch > > > > > length=3648, align1=0, align2=25: 72.91 83.99 > > > > > length=3712, align1=0, align2=26: 72.52 84.92 > > > > > length=3776, align1=0, align2=27: 76.16 84.02 > > > > > length=3840, align1=0, align2=28: 75.44 90.13 > > > > > length=3904, align1=0, align2=29: 81.62 84.43 > > > > > length=3968, align1=0, align2=30: 76.82 93.39 > > > > > length=4032, align1=0, align2=31: 80.01 89.89 > > > > > length=4096, align1=0, align2=32: 72.89 97.50 > > > > > > > > On Intel Core i7-1165G7 (Tiger Lake), I got > > > > > > Where the original numbers icl or tgl? But was just wondering > > > > Here are numbers on Core i7-1065G7 (Ice Lake): > > > > __memcpy_evex_unaligned_erms __memcpy_erms > > length=2048, align1=0, align2=0: 21.51 22.52 > > length=2048, align1=0, align2=0: 22.11 21.50 > > length=2048, align1=0, align2=0: 21.96 22.10 > > length=2048, align1=0, align2=0: 22.58 21.51 > > length=2112, align1=0, align2=0: 24.20 24.40 > > length=2112, align1=1, align2=0: 26.07 23.13 > > length=2112, align1=0, align2=1: 27.18 28.13 > > length=2112, align1=1, align2=1: 26.23 25.16 > > length=2176, align1=0, align2=0: 23.18 22.52 > > length=2176, align1=2, align2=0: 25.45 22.52 > > length=2176, align1=0, align2=2: 27.14 35.82 > > length=2176, align1=2, align2=2: 22.73 25.56 > > length=2240, align1=0, align2=0: 24.62 24.25 > > length=2240, align1=3, align2=0: 29.77 27.15 > > length=2240, align1=0, align2=3: 35.55 29.93 > > length=2240, align1=3, align2=3: 34.49 25.15 > > length=2304, align1=0, align2=0: 34.75 26.64 > > length=2304, align1=4, align2=0: 32.09 22.63 > > length=2304, align1=0, align2=4: 28.43 31.24 > > length=2304, align1=4, align2=4: 23.95 25.56 > > length=2368, align1=0, align2=0: 25.57 24.34 > > length=2368, align1=5, align2=0: 30.57 23.94 > > length=2368, align1=0, align2=5: 31.29 31.24 > > length=2368, align1=5, align2=5: 25.57 26.69 > > length=2432, align1=0, align2=0: 25.16 23.77 > > length=2432, align1=6, align2=0: 29.27 23.13 > > length=2432, align1=0, align2=6: 30.40 33.77 > > length=2432, align1=6, align2=6: 25.16 26.37 > > length=2496, align1=0, align2=0: 26.85 24.34 > > length=2496, align1=7, align2=0: 32.04 24.75 > > length=2496, align1=0, align2=7: 32.70 33.06 > > length=2496, align1=7, align2=7: 26.79 25.97 > > length=2560, align1=0, align2=0: 61.84 23.53 > > length=2560, align1=8, align2=0: 30.74 23.53 > > length=2560, align1=0, align2=8: 33.35 35.44 > > length=2560, align1=8, align2=8: 27.94 27.52 > > length=2624, align1=0, align2=0: 27.60 24.75 > > length=2624, align1=9, align2=0: 33.28 25.16 > > length=2624, align1=0, align2=9: 34.14 34.48 > > length=2624, align1=9, align2=9: 28.00 26.78 > > length=2688, align1=0, align2=0: 38.94 24.61 > > length=2688, align1=10, align2=0: 31.23 23.94 > > length=2688, align1=0, align2=10: 33.89 37.11 > > length=2688, align1=10, align2=10: 28.40 27.18 > > length=2752, align1=0, align2=0: 36.17 25.56 > > length=2752, align1=11, align2=0: 35.88 25.57 > > length=2752, align1=0, align2=11: 35.40 36.11 > > length=2752, align1=11, align2=11: 28.82 27.94 > > length=2816, align1=0, align2=0: 33.78 24.54 > > length=2816, align1=12, align2=0: 33.75 25.96 > > length=2816, align1=0, align2=12: 34.24 37.73 > > length=2816, align1=12, align2=12: 29.22 27.59 > > length=2880, align1=0, align2=0: 39.76 25.97 > > length=2880, align1=13, align2=0: 41.26 26.66 > > length=2880, align1=0, align2=13: 40.72 37.73 > > length=2880, align1=13, align2=13: 35.13 27.59 > > length=2944, align1=0, align2=0: 32.09 24.75 > > length=2944, align1=14, align2=0: 40.27 26.78 > > length=2944, align1=0, align2=14: 45.59 39.55 > > length=2944, align1=14, align2=14: 40.94 28.00 > > length=3008, align1=0, align2=0: 42.17 25.97 > > length=3008, align1=15, align2=0: 41.81 27.07 > > length=3008, align1=0, align2=15: 42.67 39.35 > > length=3008, align1=15, align2=15: 42.18 28.00 > > length=3072, align1=0, align2=0: 34.71 25.16 > > length=3072, align1=16, align2=0: 43.31 26.37 > > length=3072, align1=0, align2=16: 43.41 40.98 > > length=3072, align1=16, align2=16: 36.62 27.99 > > length=3136, align1=0, align2=0: 45.75 26.78 > > length=3136, align1=17, align2=0: 43.29 27.59 > > length=3136, align1=0, align2=17: 44.44 41.16 > > length=3136, align1=17, align2=17: 34.99 28.59 > > length=3200, align1=0, align2=0: 43.12 25.16 > > length=3200, align1=18, align2=0: 43.04 27.59 > > length=3200, align1=0, align2=18: 45.08 42.59 > > length=3200, align1=18, align2=18: 36.00 28.81 > > length=3264, align1=0, align2=0: 43.01 27.48 > > length=3264, align1=19, align2=0: 47.72 28.61 > > length=3264, align1=0, align2=19: 47.00 42.60 > > length=3264, align1=19, align2=19: 44.44 28.81 > > length=3328, align1=0, align2=0: 35.50 25.75 > > length=3328, align1=20, align2=0: 44.84 27.19 > > length=3328, align1=0, align2=20: 46.38 44.41 > > length=3328, align1=20, align2=20: 33.68 28.81 > > length=3392, align1=0, align2=0: 43.82 27.18 > > length=3392, align1=21, align2=0: 45.91 28.81 > > length=3392, align1=0, align2=21: 47.61 43.06 > > length=3392, align1=21, align2=21: 43.82 29.21 > > length=3456, align1=0, align2=0: 43.83 26.64 > > length=3456, align1=22, align2=0: 44.77 29.49 > > length=3456, align1=0, align2=22: 47.57 46.01 > > length=3456, align1=22, align2=22: 44.11 29.62 > > length=3520, align1=0, align2=0: 45.04 27.99 > > length=3520, align1=23, align2=0: 46.59 30.55 > > length=3520, align1=0, align2=23: 50.58 44.80 > > length=3520, align1=23, align2=23: 43.85 29.21 > > length=3584, align1=0, align2=0: 45.04 26.88 > > length=3584, align1=24, align2=0: 47.22 29.21 > > length=3584, align1=0, align2=24: 50.12 47.47 > > length=3584, align1=24, align2=24: 45.04 29.80 > > length=3648, align1=0, align2=0: 47.13 28.40 > > length=3648, align1=25, align2=0: 48.78 30.94 > > length=3648, align1=0, align2=25: 49.25 61.42 > > length=3648, align1=25, align2=25: 45.85 30.02 > > length=3712, align1=0, align2=0: 47.24 27.19 > > length=3712, align1=26, align2=0: 48.41 30.79 > > length=3712, align1=0, align2=26: 49.65 51.57 > > length=3712, align1=26, align2=26: 48.76 30.33 > > length=3776, align1=0, align2=0: 47.35 34.61 > > length=3776, align1=27, align2=0: 49.16 31.99 > > length=3776, align1=0, align2=27: 52.06 49.38 > > length=3776, align1=27, align2=27: 47.36 30.43 > > length=3840, align1=0, align2=0: 49.70 28.35 > > length=3840, align1=28, align2=0: 50.29 31.81 > > length=3840, align1=0, align2=28: 51.15 50.71 > > length=3840, align1=28, align2=28: 47.07 31.65 > > length=3904, align1=0, align2=0: 48.28 29.21 > > length=3904, align1=29, align2=0: 51.96 32.99 > > length=3904, align1=0, align2=29: 53.24 50.71 > > length=3904, align1=29, align2=29: 47.88 31.64 > > length=3968, align1=0, align2=0: 47.89 29.19 > > length=3968, align1=30, align2=0: 51.52 32.57 > > length=3968, align1=0, align2=30: 54.03 52.33 > > length=3968, align1=30, align2=30: 46.62 33.15 > > length=4032, align1=0, align2=0: 49.77 29.62 > > length=4032, align1=31, align2=0: 53.62 34.27 > > length=4032, align1=0, align2=31: 56.44 52.33 > > length=4032, align1=31, align2=31: 48.94 33.16 > > length=4096, align1=0, align2=0: 49.37 29.21 > > length=4096, align1=32, align2=0: 50.46 33.00 > > length=4096, align1=0, align2=32: 49.31 55.14 > > length=4096, align1=32, align2=32: 49.28 33.05 > > > > > if the align2 != 0, align1 = 0 case on Icelake warranted more investigation. > > > That being said the change is a clear winner on Icelake as well > > > for any other alignment schema. > > > > True, REP MOVSB is more efficient. > > > > This is the v2 patch I am checking in next week. Sorry! LGTM. Change is a big net gain :) > > Thanks. > > -- > H.J.