From patchwork Thu Jan 16 17:58:35 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Christophe Leroy X-Patchwork-Id: 11337605 Return-Path: Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 6485813BD for ; Thu, 16 Jan 2020 18:41:06 +0000 (UTC) Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 1F9292081E for ; Thu, 16 Jan 2020 18:41:06 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=lists.infradead.org header.i=@lists.infradead.org header.b="qfJQlOxI"; dkim=fail reason="signature verification failed" (1024-bit key) header.d=c-s.fr header.i=@c-s.fr header.b="mvz9xrLo" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 1F9292081E Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=c-s.fr Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-arm-kernel-bounces+patchwork-linux-arm=patchwork.kernel.org@lists.infradead.org DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20170209; h=Sender: Content-Transfer-Encoding:Content-Type:MIME-Version:Cc:List-Subscribe: List-Help:List-Post:List-Archive:List-Unsubscribe:List-Id:Date:To:Subject: From:References:In-Reply-To:Message-Id:Reply-To:Content-ID: Content-Description:Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc :Resent-Message-ID:List-Owner; bh=HOKQARsxycRH76L2tBslqdMNkitjZuMXDAd9KcqBmsI=; b=qfJQlOxIbIJbvc/nsDZllMFPN5 z3t6A5THk7dqg5xDOs1mS9L7xsLVIHOuJG3Ue/ONH9VvvTJyaabFgiuPWNTRJqAs6ml1Z6OyFTeB0 b+HIDUev5xkG7Sef1akKcW2a6ck3on9HpWEDs2In4qHkNBPJLFGqv/FKkWQ/VIiI/FlJ5gHr6rSbB aiLL+RIwkPwtI4CP/s4wUtnXMN2+p2reXvsleceDxm1LN7UaIY1wQlWORspTCjuAOj+/yWWWfj1u1 ub+fyfKQ3L+JLMbjv1Wk5KRw0tzASN5aPu4md3tRODttbx6HulCOj0NWTJWV1MBGrzud50GUDMJuq nnzvoljA==; Received: from localhost ([127.0.0.1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.92.3 #3 (Red Hat Linux)) id 1isA4k-0003HF-Mw; Thu, 16 Jan 2020 18:41:02 +0000 Received: from pegase1.c-s.fr ([93.17.236.30]) by bombadil.infradead.org with esmtps (Exim 4.92.3 #3 (Red Hat Linux)) id 1is9Pn-0002nh-0Y for linux-arm-kernel@lists.infradead.org; Thu, 16 Jan 2020 17:58:54 +0000 Received: from localhost (mailhub1-int [192.168.12.234]) by localhost (Postfix) with ESMTP id 47zBky4VNBz9v4gv; Thu, 16 Jan 2020 18:58:34 +0100 (CET) Authentication-Results: localhost; dkim=pass reason="1024-bit key; insecure key" header.d=c-s.fr header.i=@c-s.fr header.b=mvz9xrLo; dkim-adsp=pass; dkim-atps=neutral X-Virus-Scanned: Debian amavisd-new at c-s.fr Received: from pegase1.c-s.fr ([192.168.12.234]) by localhost (pegase1.c-s.fr [192.168.12.234]) (amavisd-new, port 10024) with ESMTP id 1jI1zVr3Jr4A; Thu, 16 Jan 2020 18:58:34 +0100 (CET) Received: from messagerie.si.c-s.fr (messagerie.si.c-s.fr [192.168.25.192]) by pegase1.c-s.fr (Postfix) with ESMTP id 47zBky3SmDz9v4gc; Thu, 16 Jan 2020 18:58:34 +0100 (CET) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=c-s.fr; s=mail; t=1579197514; bh=Q6VcAWUVvKepnLf+FFNXtla3CmiLjseY/gtHLv0ppEk=; h=In-Reply-To:References:From:Subject:To:Cc:Date:From; b=mvz9xrLoDf0x9ZlRq7P/56z1YhzUJALo3sg1YXCoFGHBXpwEiqEWD2vNUYaVeXaqM HYDPZtGmygVj1DPIUGjZPFe3z+lhw+HicfayDrRiDhPSzKuwkBeiCfW5vjXVXqm5f/ g1fS2mNXaEY/h0bq58iMBkV7Q/TExNK6gb7mWlbE= Received: from localhost (localhost [127.0.0.1]) by messagerie.si.c-s.fr (Postfix) with ESMTP id 1E37F8B82D; Thu, 16 Jan 2020 18:58:36 +0100 (CET) X-Virus-Scanned: amavisd-new at c-s.fr Received: from messagerie.si.c-s.fr ([127.0.0.1]) by localhost (messagerie.si.c-s.fr [127.0.0.1]) (amavisd-new, port 10023) with ESMTP id ioD9o1OpiPdY; Thu, 16 Jan 2020 18:58:36 +0100 (CET) Received: from po14934vm.idsi0.si.c-s.fr (unknown [192.168.4.90]) by messagerie.si.c-s.fr (Postfix) with ESMTP id D80428B82A; Thu, 16 Jan 2020 18:58:35 +0100 (CET) Received: by po14934vm.idsi0.si.c-s.fr (Postfix, from userid 0) id AC38F64A33; Thu, 16 Jan 2020 17:58:35 +0000 (UTC) Message-Id: <29f979e09c84c95f08fcd15386576e32c546d04b.1579196675.git.christophe.leroy@c-s.fr> In-Reply-To: References: From: Christophe Leroy Subject: [RFC PATCH v4 11/11] powerpc/32: provide vdso_shift_ns() To: Benjamin Herrenschmidt , Paul Mackerras , Michael Ellerman , nathanl@linux.ibm.com, arnd@arndb.de, tglx@linutronix.de, vincenzo.frascino@arm.com, luto@kernel.org Date: Thu, 16 Jan 2020 17:58:35 +0000 (UTC) X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20200116_095843_408432_A9CCAD58 X-CRM114-Status: UNSURE ( 8.98 ) X-CRM114-Notice: Please train this message. X-Spam-Score: -0.2 (/) X-Spam-Report: SpamAssassin version 3.4.2 on bombadil.infradead.org summary: Content analysis details: (-0.2 points) pts rule name description ---- ---------------------- -------------------------------------------------- -0.0 RCVD_IN_DNSWL_NONE RBL: Sender listed at https://www.dnswl.org/, no trust [93.17.236.30 listed in list.dnswl.org] -0.0 SPF_PASS SPF: sender matches SPF record 0.0 SPF_HELO_NONE SPF: HELO does not publish an SPF Record -0.1 DKIM_VALID_AU Message has a valid DKIM or DK signature from author's domain 0.1 DKIM_SIGNED Message has a DKIM or DK signature, not necessarily valid -0.1 DKIM_VALID Message has at least one valid DKIM or DK signature -0.1 DKIM_VALID_EF Message has a valid DKIM or DK signature from envelope-from domain X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: x86@kernel.org, linuxppc-dev@lists.ozlabs.org, linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-mips@vger.kernel.org MIME-Version: 1.0 Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+patchwork-linux-arm=patchwork.kernel.org@lists.infradead.org The generic x >> s gives the following result: 18: 35 25 ff e0 addic. r9,r5,-32 1c: 41 80 00 10 blt 2c 20: 7c 64 4c 30 srw r4,r3,r9 24: 38 60 00 00 li r3,0 ... 2c: 54 69 08 3c rlwinm r9,r3,1,0,30 30: 21 45 00 1f subfic r10,r5,31 34: 7c 84 2c 30 srw r4,r4,r5 38: 7d 29 50 30 slw r9,r9,r10 3c: 7c 63 2c 30 srw r3,r3,r5 40: 7d 24 23 78 or r4,r9,r4 In our case the shift is always < 32. In addition, the upper 32 bits of the result are likely nul. Lets GCC know it, it also optimises the following calculations. With the patch, we get: 0: 21 25 00 20 subfic r9,r5,32 4: 7c 69 48 30 slw r9,r3,r9 8: 7c 84 2c 30 srw r4,r4,r5 c: 7d 24 23 78 or r4,r9,r4 10: 7c 63 2c 30 srw r3,r3,r5 Performance before the patch: clock-gettime-realtime: vdso: 1033 nsec/call After the patch: clock-gettime-realtime: vdso: 941 nsec/call Signed-off-by: Christophe Leroy --- arch/powerpc/include/asm/vdso/gettimeofday.h | 17 +++++++++++++++++ 1 file changed, 17 insertions(+) diff --git a/arch/powerpc/include/asm/vdso/gettimeofday.h b/arch/powerpc/include/asm/vdso/gettimeofday.h index 74b6eef8fbe9..716a137ab166 100644 --- a/arch/powerpc/include/asm/vdso/gettimeofday.h +++ b/arch/powerpc/include/asm/vdso/gettimeofday.h @@ -95,6 +95,23 @@ static __always_inline u64 vdso_calc_delta(u64 cycles, u64 last, u64 mask, u32 m } #define vdso_calc_delta vdso_calc_delta +#ifndef __powerpc64__ +static __always_inline u64 vdso_shift_ns(u64 ns, unsigned long shift) +{ + u32 hi = ns >> 32; + u32 lo = ns; + + lo = (lo >> shift) | (hi << (32 - shift)); + hi >>= shift; + + if (likely(hi == 0)) + return lo; + + return ((u64)hi << 32) | lo; +} +#define vdso_shift_ns vdso_shift_ns +#endif + #endif /* !__ASSEMBLY__ */ #endif /* __ASM_VDSO_GETTIMEOFDAY_H */