From patchwork Mon Jan 13 17:08:42 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Christophe Leroy X-Patchwork-Id: 11330581 X-Patchwork-Delegate: paulburton@kernel.org 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 8839D138D for ; Mon, 13 Jan 2020 17:08:47 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 6620021739 for ; Mon, 13 Jan 2020 17:08:47 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=c-s.fr header.i=@c-s.fr header.b="RhThshVb" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728797AbgAMRIp (ORCPT ); Mon, 13 Jan 2020 12:08:45 -0500 Received: from pegase1.c-s.fr ([93.17.236.30]:40965 "EHLO pegase1.c-s.fr" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728774AbgAMRIp (ORCPT ); Mon, 13 Jan 2020 12:08:45 -0500 Received: from localhost (mailhub1-int [192.168.12.234]) by localhost (Postfix) with ESMTP id 47xKmk07Phz9txyw; Mon, 13 Jan 2020 18:08:38 +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=RhThshVb; 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 hi6YDy-nSTFK; Mon, 13 Jan 2020 18:08:37 +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 47xKmj68nxz9txyq; Mon, 13 Jan 2020 18:08:37 +0100 (CET) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=c-s.fr; s=mail; t=1578935317; bh=aRVCODNqlpogffdcxAo9rl2jrXtK1fAZ2Yi8uLoDcQI=; h=In-Reply-To:References:From:Subject:To:Cc:Date:From; b=RhThshVbUL4jv+5S+SxWZzpxtdMaaFBZAob5AEBGqwjBsuHm1Wx+s+wNNOGbyb8Q5 4Te2ejtiGvX8509XCo5J8GSBHWfFu6v/aQQFmgOxj5BGbYNc8lQPKjaNoPy8gV3mwo FX0G38hQ5jQO+raWCdy2z6YMeXqRUvBTTTsbbSMk= Received: from localhost (localhost [127.0.0.1]) by messagerie.si.c-s.fr (Postfix) with ESMTP id 309198B7C9; Mon, 13 Jan 2020 18:08:43 +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 uDhYnHcG98bc; Mon, 13 Jan 2020 18:08:43 +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 DDE338B7BE; Mon, 13 Jan 2020 18:08:42 +0100 (CET) Received: by localhost.localdomain (Postfix, from userid 0) id AD1B964A1D; Mon, 13 Jan 2020 17:08:42 +0000 (UTC) Message-Id: <25d3e027aeef5cdbe1b205ecfbf8d80270fc2bd9.1578934751.git.christophe.leroy@c-s.fr> In-Reply-To: References: From: Christophe Leroy Subject: [RFC PATCH v3 04/12] lib: vdso: inline do_hres() and do_coarse() To: Benjamin Herrenschmidt , Paul Mackerras , Michael Ellerman , arnd@arndb.de, tglx@linutronix.de, vincenzo.frascino@arm.com, luto@kernel.org Cc: linux-kernel@vger.kernel.org, linuxppc-dev@lists.ozlabs.org, linux-arm-kernel@lists.infradead.org, linux-mips@vger.kernel.org, x86@kernel.org Date: Mon, 13 Jan 2020 17:08:42 +0000 (UTC) Sender: linux-mips-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-mips@vger.kernel.org do_hres() is called from several places, so GCC doesn't inline it at first. do_hres() takes a struct __kernel_timespec * parameter for passing the result. In the 32 bits case, this parameter corresponds to a local var in the caller. In order to provide a pointer to this structure, the caller has to put it in its stack and do_hres() has to write the result in the stack. This is suboptimal, especially on RISC processor like powerpc. By making GCC inline the function, the struct __kernel_timespec remains a local var using registers, avoiding the need to write and read stack. The improvement is significant on powerpc: Before: gettimeofday: vdso: 1379 nsec/call clock-gettime-realtime-coarse: vdso: 868 nsec/call clock-gettime-realtime: vdso: 1511 nsec/call clock-gettime-monotonic-raw: vdso: 1576 nsec/call After: gettimeofday: vdso: 1078 nsec/call clock-gettime-realtime-coarse: vdso: 807 nsec/call clock-gettime-realtime: vdso: 1256 nsec/call clock-gettime-monotonic-raw: vdso: 1316 nsec/call At the same time, change the return type of do_coarse() to int, this increase readability of the if/elseif/elseif/else section in __cvdso_clock_gettime_common() Signed-off-by: Christophe Leroy --- lib/vdso/gettimeofday.c | 29 ++++++++++++++++------------- 1 file changed, 16 insertions(+), 13 deletions(-) diff --git a/lib/vdso/gettimeofday.c b/lib/vdso/gettimeofday.c index 42bd8ab955fa..d75e44ba716f 100644 --- a/lib/vdso/gettimeofday.c +++ b/lib/vdso/gettimeofday.c @@ -38,8 +38,8 @@ u64 vdso_calc_delta(u64 cycles, u64 last, u64 mask, u32 mult) } #endif -static int do_hres(const struct vdso_data *vd, clockid_t clk, - struct __kernel_timespec *ts) +static __always_inline int do_hres(const struct vdso_data *vd, clockid_t clk, + struct __kernel_timespec *ts) { const struct vdso_timestamp *vdso_ts = &vd->basetime[clk]; u64 cycles, last, sec, ns; @@ -68,8 +68,8 @@ static int do_hres(const struct vdso_data *vd, clockid_t clk, return 0; } -static void do_coarse(const struct vdso_data *vd, clockid_t clk, - struct __kernel_timespec *ts) +static __always_inline int do_coarse(const struct vdso_data *vd, clockid_t clk, + struct __kernel_timespec *ts) { const struct vdso_timestamp *vdso_ts = &vd->basetime[clk]; u32 seq; @@ -79,6 +79,8 @@ static void do_coarse(const struct vdso_data *vd, clockid_t clk, ts->tv_sec = vdso_ts->sec; ts->tv_nsec = vdso_ts->nsec; } while (unlikely(vdso_read_retry(vd, seq))); + + return 0; } static __maybe_unused int @@ -96,15 +98,16 @@ __cvdso_clock_gettime_common(clockid_t clock, struct __kernel_timespec *ts) * clocks are handled in the VDSO directly. */ msk = 1U << clock; - if (likely(msk & VDSO_HRES)) { - return do_hres(&vd[CS_HRES_COARSE], clock, ts); - } else if (msk & VDSO_COARSE) { - do_coarse(&vd[CS_HRES_COARSE], clock, ts); - return 0; - } else if (msk & VDSO_RAW) { - return do_hres(&vd[CS_RAW], clock, ts); - } - return -1; + if (likely(msk & VDSO_HRES)) + vd += CS_HRES_COARSE; + else if (msk & VDSO_COARSE) + return do_coarse(&vd[CS_HRES_COARSE], clock, ts); + else if (msk & VDSO_RAW) + vd += CS_RAW; + else + return -1; + + return do_hres(vd, clock, ts); } static __maybe_unused int