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 X-Spam-Level: X-Spam-Status: No, score=-2.2 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, USER_AGENT_SANE_1 autolearn=no 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 3830EC35240 for ; Sun, 2 Feb 2020 03:29:43 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 04FD5206E3 for ; Sun, 2 Feb 2020 03:29:43 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=kernel-dk.20150623.gappssmtp.com header.i=@kernel-dk.20150623.gappssmtp.com header.b="dlCGRvnX" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726805AbgBBD3m (ORCPT ); Sat, 1 Feb 2020 22:29:42 -0500 Received: from mail-pl1-f193.google.com ([209.85.214.193]:44420 "EHLO mail-pl1-f193.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726784AbgBBD3m (ORCPT ); Sat, 1 Feb 2020 22:29:42 -0500 Received: by mail-pl1-f193.google.com with SMTP id d9so4421263plo.11 for ; Sat, 01 Feb 2020 19:29:42 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel-dk.20150623.gappssmtp.com; s=20150623; h=subject:to:references:from:message-id:date:user-agent:mime-version :in-reply-to:content-language:content-transfer-encoding; bh=YBIXjIqgaXFsUqKN5BtwpscrVymGECQYBGc96ukAT1E=; b=dlCGRvnXqcPtYNJfSVRHsdCmQqnWfyqC4muQ1l3TB655FsWS7WQcxNEJXvBgw7zkcp 2H6qTwfhrTOsoW5yOYpXQ/so+nEkvwhDHjznTPHhPAJ3xG+aIA6c6DyiaxwQIE7Skojl gwqUq2yaciMdUy5kp2DcWPqvSpWNEvqpKuIVQfEa6WR+9Q8UgByDnrCG+lOdd+Dl6W6l O7h6NqQ6YCINw0TEX2BCudXtbETRa5NNFpItr9wvqCOkPvYQbq0q/lS/lu3FL4jqxueE yCPzAI1SrW/0fEVlYYnPPU/XDNNQHu5JpbfAdmmM3uvXNfMUGnCXIcB2TifLRhL+hqdM 7M9A== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; 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=YBIXjIqgaXFsUqKN5BtwpscrVymGECQYBGc96ukAT1E=; b=k2Rn1pGthOTLk/pJWGBY4Jx/JsNVDSxmF9O2W54yIgsXFuWxn3vtI3GBl8D93rIBpa bnP5VUfWaX+r4pYaSxthunwRF1KycbCdmFUOpff8VYW/pa0rHch4D6MG9IyXoVtkFWxQ 5VAq+eB9izR2wOkj2WrUmWon6/oF9DigDenwxdXFyLEjF6dHqM+zRXovICRyZYRL6wpE gh2KNNdVk6oYPlYtgNOnxsgIw/VEkruGksbdQmMR+pePl547kRA9m+0l8o6rxKoWxGmA E4bS9MaoG/C85YHTwMZ6Jd84lYED3KU/khCwUqN0/K+imcL4vAqghHyQaMpUlnXFfiNF mFjw== X-Gm-Message-State: APjAAAUshiYRcieKEwHLdpPZMItkRnMs6ZmNlUhis0nPpxJ3O7n5AQMe NwFRNwwERWJAXNgUAVPPyUbuuSi9RGE= X-Google-Smtp-Source: APXvYqz4mP3xmhhIUXR7/ipNuBFO8jq8kIvil+yGANTXOFuIJBUJuSUJ8ivt99InAuTPlUTQCp65HQ== X-Received: by 2002:a17:90a:b010:: with SMTP id x16mr22346061pjq.130.1580614181389; Sat, 01 Feb 2020 19:29:41 -0800 (PST) Received: from [192.168.1.188] ([66.219.217.145]) by smtp.gmail.com with ESMTPSA id a195sm15305784pfa.120.2020.02.01.19.29.40 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Sat, 01 Feb 2020 19:29:40 -0800 (PST) Subject: Re: liburing: expose syscalls? To: Pavel Begunkov , Andres Freund , io-uring@vger.kernel.org References: <20200201125350.vkkhezidm6ka6ux5@alap3.anarazel.de> <78A9EC3E-0961-4EF3-A226-1FCA34FAF818@anarazel.de> <6f5abe8a-1897-123d-d01d-d8c7c5fba7c4@gmail.com> <9644308d-ef0e-1b94-9a3b-1a4e03bfd314@gmail.com> From: Jens Axboe Message-ID: <502b2b01-d691-b7bf-53f1-e7a24fb4c6d9@kernel.dk> Date: Sat, 1 Feb 2020 20:29:39 -0700 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.4.1 MIME-Version: 1.0 In-Reply-To: <9644308d-ef0e-1b94-9a3b-1a4e03bfd314@gmail.com> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit Sender: io-uring-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: io-uring@vger.kernel.org On 2/1/20 4:30 PM, Pavel Begunkov wrote: > On 02/02/2020 01:51, Jens Axboe wrote: >>>> So you just want to have them exposed? I'd be fine with that. I'll >>>> take a patch :-) >>>> >>> >>> Depends on how it's used, but I'd strive to inline >>> __sys_io_uring_enter() to remove the extra indirect call into the >>> shared lib. Though, not sure about packaging and all this stuff. May >>> be useful to do that for liburing as well. >> >> Not sure that actually matters when you're doing a syscall anyway, that >> should be the long pole for the operation. >> > > Yeah, but they are starting to stack up (+syscall() from glibc) and can became > even more layered on the user side. Not saying it's free, just that I expect the actual system call to dominate. But I hear what you are saying, this is exactly why the liburing hot path resides in static inline code, and doesn't require library calls. I did draw the line on anything that needs a system call, figuring that wasn't worth over-optimizing. I could be full of shit, numbers talk! -- Jens Axboe