From patchwork Thu Feb 25 13:56:59 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Yury Norov X-Patchwork-Id: 12104165 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=-15.7 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_GIT 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 813FBC433E0 for ; Thu, 25 Feb 2021 13:57:57 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 38D8264F18 for ; Thu, 25 Feb 2021 13:57:57 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231721AbhBYN5x (ORCPT ); Thu, 25 Feb 2021 08:57:53 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:46730 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231248AbhBYN5q (ORCPT ); Thu, 25 Feb 2021 08:57:46 -0500 Received: from mail-qt1-x82d.google.com (mail-qt1-x82d.google.com [IPv6:2607:f8b0:4864:20::82d]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 66444C06174A; Thu, 25 Feb 2021 05:57:06 -0800 (PST) Received: by mail-qt1-x82d.google.com with SMTP id w1so4099148qto.2; Thu, 25 Feb 2021 05:57:06 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=from:to:cc:subject:date:message-id:in-reply-to:references :mime-version:content-transfer-encoding; bh=B+Er2AMgvvg9wNih89ONA7/yh52BeqTQADmg6hQCNNk=; b=oANFhxvwcRf+H93mDQVdIHtrafrmXMO69qpuNH5wFtBiIk65oCljFf3wn0j9jWD8Jf xn773fkXJ5cBecoo8uOiGVpVCd00OKIG+d/kDiqhzaL2TAP9FyYPMdmUPtcF+ogzFkPL es0Tc7y/WEes/sMCApl5bUip4fDutrrP3R0PZJ4JgJ00N+RMCEqK+DNA9AdpAnhPfl+w dVIhFJFqSCTCZEepp/T3/mXx1z5U3ubcmCMBf6t5yJxmvT7cZUHy6rjLdJh6/PzYLgG9 yFiuCDoMYIdVI33U7YCIGPueqX1+1YpI0ifvCK5aWl7TbDuBok5CUIQ0bNVadRTvBEgI bgMQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:cc:subject:date:message-id:in-reply-to :references:mime-version:content-transfer-encoding; bh=B+Er2AMgvvg9wNih89ONA7/yh52BeqTQADmg6hQCNNk=; b=FNQm+WEof1rMAzjgc9um6m5fLF+EexfiVUb+VilvmsYLjkM6hjUVDLafcCET1lt9Xv KW8E8VA8SwBP3MoIit9u01TSBrL1TgV/uvH97duhmIhK4EDNJPG+gZ6IOyLWnREqmCgE r09J0OlgcZsG4AMexm7bm+REuej2Mt48RnA/d1R6jiGTAce6VoShGkKi3Ecbdp89x6BA cohy3+R9CDLXkpzzaF21+r+CYo7QrjXPk6BRQQtCkkqU5RhP6ZUVBeZx1GFpZuHNDqzY 63yVBmEdLIsbGkaVaHvSJtk8AV0/h8Qprn3e60wlhOjG5myT6h0WjLCMY3GVVE2YUjAo 3vNQ== X-Gm-Message-State: AOAM532fgdBOwFpDebfhImAtwMnntzl0k/EcfqUQEixymIdzYXpjgb6+ Rw1DvEDHVddQM4wpYny01s0= X-Google-Smtp-Source: ABdhPJx245qzXjqscdkfz2xTv/fJGcyhYJpB7sYfuTawFg2dSpSKA/6rKwLo4Qv96QoYYrlnwcVfbw== X-Received: by 2002:ac8:6958:: with SMTP id n24mr2377747qtr.110.1614261425391; Thu, 25 Feb 2021 05:57:05 -0800 (PST) Received: from localhost (d27-96-190-162.evv.wideopenwest.com. [96.27.162.190]) by smtp.gmail.com with ESMTPSA id f17sm3514072qtv.93.2021.02.25.05.57.04 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 25 Feb 2021 05:57:05 -0800 (PST) From: Yury Norov To: Will Deacon , Catalin Marinas , Thomas Bogendoerfer , Alexander Lobakin , Alexey Klimov , linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, linux-arch@vger.kernel.org, linux-mips@vger.kernel.org Cc: Yury Norov Subject: [RESEND PATCH 1/2] ARM64: enable GENERIC_FIND_FIRST_BIT Date: Thu, 25 Feb 2021 05:56:59 -0800 Message-Id: <20210225135700.1381396-2-yury.norov@gmail.com> X-Mailer: git-send-email 2.25.1 In-Reply-To: <20210225135700.1381396-1-yury.norov@gmail.com> References: <20210225135700.1381396-1-yury.norov@gmail.com> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-mips@vger.kernel.org ARM64 doesn't implement find_first_{zero}_bit in arch code and doesn't enable it in a config. It leads to using find_next_bit() which is less efficient: 0000000000000000 : 0: aa0003e4 mov x4, x0 4: aa0103e0 mov x0, x1 8: b4000181 cbz x1, 38 c: f9400083 ldr x3, [x4] 10: d2800802 mov x2, #0x40 // #64 14: 91002084 add x4, x4, #0x8 18: b40000c3 cbz x3, 30 1c: 14000008 b 3c 20: f8408483 ldr x3, [x4], #8 24: 91010045 add x5, x2, #0x40 28: b50000c3 cbnz x3, 40 2c: aa0503e2 mov x2, x5 30: eb02001f cmp x0, x2 34: 54ffff68 b.hi 20 // b.pmore 38: d65f03c0 ret 3c: d2800002 mov x2, #0x0 // #0 40: dac00063 rbit x3, x3 44: dac01063 clz x3, x3 48: 8b020062 add x2, x3, x2 4c: eb02001f cmp x0, x2 50: 9a829000 csel x0, x0, x2, ls // ls = plast 54: d65f03c0 ret ... 0000000000000118 <_find_next_bit.constprop.1>: 118: eb02007f cmp x3, x2 11c: 540002e2 b.cs 178 <_find_next_bit.constprop.1+0x60> // b.hs, b.nlast 120: d346fc66 lsr x6, x3, #6 124: f8667805 ldr x5, [x0, x6, lsl #3] 128: b4000061 cbz x1, 134 <_find_next_bit.constprop.1+0x1c> 12c: f8667826 ldr x6, [x1, x6, lsl #3] 130: 8a0600a5 and x5, x5, x6 134: ca0400a6 eor x6, x5, x4 138: 92800005 mov x5, #0xffffffffffffffff // #-1 13c: 9ac320a5 lsl x5, x5, x3 140: 927ae463 and x3, x3, #0xffffffffffffffc0 144: ea0600a5 ands x5, x5, x6 148: 54000120 b.eq 16c <_find_next_bit.constprop.1+0x54> // b.none 14c: 1400000e b 184 <_find_next_bit.constprop.1+0x6c> 150: d346fc66 lsr x6, x3, #6 154: f8667805 ldr x5, [x0, x6, lsl #3] 158: b4000061 cbz x1, 164 <_find_next_bit.constprop.1+0x4c> 15c: f8667826 ldr x6, [x1, x6, lsl #3] 160: 8a0600a5 and x5, x5, x6 164: eb05009f cmp x4, x5 168: 540000c1 b.ne 180 <_find_next_bit.constprop.1+0x68> // b.any 16c: 91010063 add x3, x3, #0x40 170: eb03005f cmp x2, x3 174: 54fffee8 b.hi 150 <_find_next_bit.constprop.1+0x38> // b.pmore 178: aa0203e0 mov x0, x2 17c: d65f03c0 ret 180: ca050085 eor x5, x4, x5 184: dac000a5 rbit x5, x5 188: dac010a5 clz x5, x5 18c: 8b0300a3 add x3, x5, x3 190: eb03005f cmp x2, x3 194: 9a839042 csel x2, x2, x3, ls // ls = plast 198: aa0203e0 mov x0, x2 19c: d65f03c0 ret ... 0000000000000238 : 238: a9bf7bfd stp x29, x30, [sp, #-16]! 23c: aa0203e3 mov x3, x2 240: d2800004 mov x4, #0x0 // #0 244: aa0103e2 mov x2, x1 248: 910003fd mov x29, sp 24c: d2800001 mov x1, #0x0 // #0 250: 97ffffb2 bl 118 <_find_next_bit.constprop.1> 254: a8c17bfd ldp x29, x30, [sp], #16 258: d65f03c0 ret Enabling find_{first,next}_bit() would also benefit for_each_{set,clear}_bit(). On A-53 find_first_bit() is almost twice faster than find_next_bit(), according to lib/find_bit_benchmark (thanks to Alexey for testing): GENERIC_FIND_FIRST_BIT=n: [7126084.948181] find_first_bit: 47389224 ns, 16357 iterations [7126085.032315] find_first_bit: 19048193 ns, 655 iterations GENERIC_FIND_FIRST_BIT=y: [ 84.158068] find_first_bit: 27193319 ns, 16406 iterations [ 84.233005] find_first_bit: 11082437 ns, 656 iterations GENERIC_FIND_FIRST_BIT=n bloats the kernel despite that it disables generation of find_{first,next}_bit(): yury:linux$ scripts/bloat-o-meter vmlinux vmlinux.ffb add/remove: 4/1 grow/shrink: 19/251 up/down: 564/-1692 (-1128) ... Overall, GENERIC_FIND_FIRST_BIT=n is harmful both in terms of performance and code size, and it's better to have GENERIC_FIND_FIRST_BIT enabled. Tested-by: Alexey Klimov Signed-off-by: Yury Norov Acked-by: Will Deacon --- arch/arm64/Kconfig | 1 + 1 file changed, 1 insertion(+) diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig index 31bd885b79eb..5596eab04092 100644 --- a/arch/arm64/Kconfig +++ b/arch/arm64/Kconfig @@ -108,6 +108,7 @@ config ARM64 select GENERIC_CPU_AUTOPROBE select GENERIC_CPU_VULNERABILITIES select GENERIC_EARLY_IOREMAP + select GENERIC_FIND_FIRST_BIT select GENERIC_IDLE_POLL_SETUP select GENERIC_IRQ_IPI select GENERIC_IRQ_MULTI_HANDLER From patchwork Thu Feb 25 13:57:00 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Yury Norov X-Patchwork-Id: 12104167 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=-15.7 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_GIT 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 1372CC433E6 for ; Thu, 25 Feb 2021 13:57:58 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id C480B64F0E for ; Thu, 25 Feb 2021 13:57:57 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231822AbhBYN54 (ORCPT ); Thu, 25 Feb 2021 08:57:56 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:46736 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231274AbhBYN5r (ORCPT ); Thu, 25 Feb 2021 08:57:47 -0500 Received: from mail-qk1-x72e.google.com (mail-qk1-x72e.google.com [IPv6:2607:f8b0:4864:20::72e]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 39662C061756; Thu, 25 Feb 2021 05:57:07 -0800 (PST) Received: by mail-qk1-x72e.google.com with SMTP id f17so5653554qkl.5; Thu, 25 Feb 2021 05:57:07 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=from:to:cc:subject:date:message-id:in-reply-to:references :mime-version:content-transfer-encoding; bh=YjQQYAvCYurZK7ldaR7wdMuQlhqNk26sh+booS2Ah34=; b=uRMIB6gDJkTYgjbHVu7BAzdGGm1PFtEAm1zu98MInx0ilMKOd79he4zUJKLVyn5GUB tlZMhqNfr5G/ILE0mA8nnhJq9AmzfJXAmQi4oBS5dxezyZR1l5Xn1oyEoao/cjg5BqrO sP+AsEjwmcT4MM333CaI0Cf5xGOa8PyZX7ueyudp64ptucBQtz7m3rPqFL8aN42MDGmo b7tIRoRtY7HBLDg8S7aXUBME8kjVgCe5DTZeoXRDRcl9MM4D7Bh7GxY2WMcjazIOmGDo nPO9CWDk4Zt5sOSjW3zTaEUgj5g5ihUB387FcuwKTBil76LwLkgVWpX4iK0iu/V+bppa 78EA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:cc:subject:date:message-id:in-reply-to :references:mime-version:content-transfer-encoding; bh=YjQQYAvCYurZK7ldaR7wdMuQlhqNk26sh+booS2Ah34=; b=Jz0QXzZ1tAt5UkcOmZabi3BUy/vEoIy5YS97RyeA8VfZQ2maEVj+/gbZHYhg5wKO5Z FSeDNSPR9QfHnKjMRhdmjKlguSgxjWYzVs1gTwQr7klatUtuatzf5GCyBJYdZ3Zv/MiK kN4/DYDtwG3LOauSxZvWdudG0b2NyBVeU+4vkwlIHdeiA4tbUj0R2eRVEJ9VWULn5HHn 3/uRYJTfVxPXGKRWuBpYfEyh9FMdWR7GtJvM77efw3v+1U+o2Vq+Cne5PaoT6pmdHcMk rPAXc24qIrBjx0pTp285mxkuF23yG1rFlsg1M/YYPu01NBH5/FhSIjbSdi6WnXkbOczw 1otw== X-Gm-Message-State: AOAM532ZTtTBUyd4rVCHtRhdR878tfHj7kh+mc0ZpR6N1QxFeQ79aAn6 H+XxzDbeQ/t1LicacA94MfY= X-Google-Smtp-Source: ABdhPJx+PKOZos9XXN2E6Yo01qJv1TAuCbOtRjCLWy1ChLGZFh7LIPlXALSkc5a6ENsIBlQSRnoD1Q== X-Received: by 2002:a05:620a:166e:: with SMTP id d14mr2846844qko.82.1614261426421; Thu, 25 Feb 2021 05:57:06 -0800 (PST) Received: from localhost (d27-96-190-162.evv.wideopenwest.com. [96.27.162.190]) by smtp.gmail.com with ESMTPSA id z1sm3522908qtu.83.2021.02.25.05.57.06 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 25 Feb 2021 05:57:06 -0800 (PST) From: Yury Norov To: Will Deacon , Catalin Marinas , Thomas Bogendoerfer , Alexander Lobakin , Alexey Klimov , linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, linux-arch@vger.kernel.org, linux-mips@vger.kernel.org Cc: Yury Norov Subject: [PATCH 2/2] MIPS: enable GENERIC_FIND_FIRST_BIT Date: Thu, 25 Feb 2021 05:57:00 -0800 Message-Id: <20210225135700.1381396-3-yury.norov@gmail.com> X-Mailer: git-send-email 2.25.1 In-Reply-To: <20210225135700.1381396-1-yury.norov@gmail.com> References: <20210225135700.1381396-1-yury.norov@gmail.com> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-mips@vger.kernel.org From: Alexander Lobakin MIPS doesn't have architecture-optimized bitsearching functions, like find_{first,next}_bit() etc. It's absolutely harmless to enable GENERIC_FIND_FIRST_BIT as this functionality is not new at all and well-tested. It provides more optimized code and saves some .text memory (32 R2): add/remove: 4/1 grow/shrink: 1/53 up/down: 216/-372 (-156) Users of for_each_set_bit() like hotpath gic_handle_shared_int() will also benefit from this. Suggested-by: Yury Norov Signed-off-by: Alexander Lobakin Signed-off-by: Yury Norov --- arch/mips/Kconfig | 1 + 1 file changed, 1 insertion(+) diff --git a/arch/mips/Kconfig b/arch/mips/Kconfig index d89efba3d8a4..164bdd715d4b 100644 --- a/arch/mips/Kconfig +++ b/arch/mips/Kconfig @@ -26,6 +26,7 @@ config MIPS select GENERIC_ATOMIC64 if !64BIT select GENERIC_CMOS_UPDATE select GENERIC_CPU_AUTOPROBE + select GENERIC_FIND_FIRST_BIT select GENERIC_GETTIMEOFDAY select GENERIC_IOMAP select GENERIC_IRQ_PROBE