From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-pf0-f195.google.com (mail-pf0-f195.google.com [209.85.192.195]) by dpdk.org (Postfix) with ESMTP id 0E2DE1B6FC for ; Tue, 30 Jan 2018 20:33:20 +0100 (CET) Received: by mail-pf0-f195.google.com with SMTP id b25so10055858pfd.9 for ; Tue, 30 Jan 2018 11:33:19 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=networkplumber-org.20150623.gappssmtp.com; s=20150623; h=date:from:to:cc:subject:message-id:in-reply-to:references :mime-version:content-transfer-encoding; bh=/y8J2izGl//gp0q7VygX9xkdtric0YHUxA9q6GACexw=; b=eTS9WRBhaGZvOu3kS9AAOFEz9VNiWIXSVc/frjEZF0RKW+YAEAesCyN5Qc9rQMJJqR W4HuUC4bffBEI+W5OHBIwmW/KxDR726XCewXJ2rUz/V2KryxyxmZU2LE+3y38Y0MLPys Z7ymc/M5x7y1jgFNqhQXo6XQuqMPVra+S90Fuq3CqWI9D9ixUf7Nd1di/jiyOnakSUej ErUTIyrLyYm0zsNcA8mif5fMIcxfyfToo7qfl7KUi7rvJiEdXPcMJjLVIqDGG2Gc2RTY Yei0uKLtFmEBVoIVkSjokLZweRRYWypAbDvfqodb8+AuFiB3I3pSrmm7QZeFD2zHnFWN ReiQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:from:to:cc:subject:message-id:in-reply-to :references:mime-version:content-transfer-encoding; bh=/y8J2izGl//gp0q7VygX9xkdtric0YHUxA9q6GACexw=; b=MEUIjBa0cdGG/G6EFwblE3fzlCLGvaW46P7mZQQX0DBJffJTcmvVEUEjBLtLbnGBd0 SbVHfhJyOntSoxFtbaz0mlWcKtMj4H71TFdJFg4fxyN6T+yJYAGMLi9/57lOpYuAmvdF 96T4F1oA6fpe39ts09LhsTmft9tctZkf9S0yqc8StwUQXrgPVWB8awVyIfvJ1CmX9TqK tVnkkQwdx7wylAOU/55YKZB0q/d+OO2QB0TDwA4EY8TAbMpMe/YLcruAcWQJAZBtT2SE vUVbySR4f+x9y+o81i0dUm/7YEojMPWpDUQ5BL5wDkEbmGGiLi9gswRSbECq8mZKTcGV RAsQ== X-Gm-Message-State: AKwxytePZkkTn68pWldVDIC7faojwHXoctCsCPcAcy5daonMCFqT+LZE kN4aCK6y9f3McaBkqg91e8LLAIKgVZo= X-Google-Smtp-Source: AH8x226rO9rS2lyMz3W3N7bx0VBsR4wsK+TVu8DQKoHs5xtcphuvgQ4/r0Ksv6HUoGLO3bPwjqzdOg== X-Received: by 10.98.225.7 with SMTP id q7mr30806305pfh.22.1517340799195; Tue, 30 Jan 2018 11:33:19 -0800 (PST) Received: from xeon-e3 ([172.92.74.152]) by smtp.gmail.com with ESMTPSA id u67sm4997590pfd.169.2018.01.30.11.33.18 (version=TLS1_2 cipher=ECDHE-RSA-CHACHA20-POLY1305 bits=256/256); Tue, 30 Jan 2018 11:33:19 -0800 (PST) Date: Tue, 30 Jan 2018 11:33:16 -0800 From: Stephen Hemminger To: Thomas Monjalon Cc: Konstantin Ananyev , dev@dpdk.org Message-ID: <20180130113316.146088f5@xeon-e3> In-Reply-To: <3552780.vzqTqTtnLr@xps> References: <1516028680-2342-3-git-send-email-konstantin.ananyev@intel.com> <1516028971-3409-1-git-send-email-konstantin.ananyev@intel.com> <3552780.vzqTqTtnLr@xps> MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Subject: Re: [dpdk-dev] [PATCH v3 2/2] eal/x86: Use lock-prefixed instructions to reduce cost of rte_smp_mb() X-BeenThere: dev@dpdk.org X-Mailman-Version: 2.1.15 Precedence: list List-Id: DPDK patches and discussions List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Tue, 30 Jan 2018 19:33:20 -0000 On Mon, 29 Jan 2018 16:47:45 +0100 Thomas Monjalon wrote: > 15/01/2018 16:09, Konstantin Ananyev: > > On x86 it is possible to use lock-prefixed instructions to get > > the similar effect as mfence. > > As pointed by Java guys, on most modern HW that gives a better > > performance than using mfence: > > https://shipilev.net/blog/2014/on-the-fence-with-dependencies/ > > That patch adopts that technique for rte_smp_mb() implementation. > > On BDW 2.2 mb_autotest on single lcore reports 2X cycle reduction, > > i.e. from ~110 to ~55 cycles per operation. > > > > Signed-off-by: Konstantin Ananyev > > Acked-by: Bruce Richardson > > Applied, thanks Does this change since lfence is one of the ways to block Spectre variant.