From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id B0FFDC433EF for ; Mon, 31 Jan 2022 19:22:25 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1359494AbiAaTWZ (ORCPT ); Mon, 31 Jan 2022 14:22:25 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:48496 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1359486AbiAaTWY (ORCPT ); Mon, 31 Jan 2022 14:22:24 -0500 Received: from mail-il1-x12e.google.com (mail-il1-x12e.google.com [IPv6:2607:f8b0:4864:20::12e]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id A0154C061714 for ; Mon, 31 Jan 2022 11:22:24 -0800 (PST) Received: by mail-il1-x12e.google.com with SMTP id d3so12307003ilr.10 for ; Mon, 31 Jan 2022 11:22:24 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel-dk.20210112.gappssmtp.com; s=20210112; h=subject:to:references:from:message-id:date:user-agent:mime-version :in-reply-to:content-language:content-transfer-encoding; bh=L4RNZbc4w/g6bRZEOvYO7HJzVWPx+tOq9WaUROcOiD0=; b=xi8lYigDAKDAxC39RiP8JcF5AbPo2ILqABwV3/YQkdWPmoj8MeUmNObgRMrOeflERO ZoF8pSTz4rwWOPHxBOGT7/nGfdNqqe+ru8R+Lim7/uoGUOfCFQbLSZmNHVYlegts+JQe zY5yH08nko1pYnpacC8fAhZ58zrbiZE+PQMGXDVTWEp/z8pq3pLquEgbe+smlwy2ui1v XiDVgESWviPj+wTc+e/dQWl+JYlBV6Q7gGpCsSInUXFvj4Jur85VoRmb98mPDoJYX94y ySl0fKatFcjJy/kVTthwWkBllnjlDptD7hSAyFtej0PaK+l3CK+5ZzM2Gt5g6LeUpL+U yUSQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:subject:to:references:from:message-id:date :user-agent:mime-version:in-reply-to:content-language :content-transfer-encoding; bh=L4RNZbc4w/g6bRZEOvYO7HJzVWPx+tOq9WaUROcOiD0=; b=u4KPCtcO8ZF9F5QXvk/x8tlu8ewY61HSe1+51ai775D5gLozJd0Z0jDA2xNn4wZ1ZJ RJOyuRYxOXt0yiqcQHS+usflBUKXnrkGzSo0x1A+Xfu3i0hI4yybzJxM3qBaR8d+kq7m 6dH8olABWAfTDVBEBNQ01dI9yLKPqUgsGbLCjMHDZzUWMIasv9DQUb6Ter9N38RrnxZz X5fxRjdDl3FFK3CJXcMZItBOdIb0Ww7MNQji/YkUR1XtK82FEHIF/p/+Ub9S4bX3x79r RTAdEPf6rMM2mz7T35Syh+oq8MZVxNwWMh0y+ckuYPyNYfoDnucrcw0XBnvedIypvdCm 1rKg== X-Gm-Message-State: AOAM5335F9RysIX0I1pz8VPWZyBMc5LS30n1ESZS8eWUO9CJKBVGYZ7l 9Dv9mUCaPzxqhWGFnq+Vc5ZQ1la+uLHCJg== X-Google-Smtp-Source: ABdhPJyj/xY4mU704/zlxrsCzWoucnK8V1IvczV4cx0aaAcncXMFTg1y8+Unv+RqgjJ59p9zc3HmgA== X-Received: by 2002:a05:6e02:1449:: with SMTP id p9mr325629ilo.289.1643656943562; Mon, 31 Jan 2022 11:22:23 -0800 (PST) Received: from [192.168.1.30] ([207.135.234.126]) by smtp.gmail.com with ESMTPSA id s10sm2211176ild.84.2022.01.31.11.22.22 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Mon, 31 Jan 2022 11:22:23 -0800 (PST) Subject: Re: FlexSC influence on io_uring To: Spencer Baugh , io-uring@vger.kernel.org References: <87o83r7n1k.fsf@catern.com> From: Jens Axboe Message-ID: Date: Mon, 31 Jan 2022 12:22:22 -0700 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.10.0 MIME-Version: 1.0 In-Reply-To: <87o83r7n1k.fsf@catern.com> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: io-uring@vger.kernel.org On 1/31/22 11:55 AM, Spencer Baugh wrote: > > Hi, > > To what extent, if any, was the FlexSC paper an influence on io_uring? > > FlexSC is described in a paper from 2010: > https://www.usenix.org/legacy/events/osdi10/tech/full_papers/Soares.pdf > > FlexSC is a system for asynchronous system calls aimed at achieving > high-performance by avoiding the cost of system calls, in particular the > locality costs of executing kernel code and user code on the same core. > > Implementation-wise, it seems broadly similar to io_uring, in that > system calls are submitted by writing to some location in memory, which > is later picked up by a syscall-execution thread (ala > IORING_SETUP_SQPOLL) which executes it and writes back the result. > > I'm just curious if there was any influence from FlexSC on io_uring. Wasn't aware of this paper, if that answers the question. The idea for async syscalls (to me) date back to the original threadlet/acall ideas from Zach Brown and Ingo, though my implementation ended up being vastly different. The API with the rings of shared memory was a pretty obvious one and not really novel, it's been used in both sw and hw for a long time. -- Jens Axboe