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 mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 70070C433F5 for ; Fri, 1 Oct 2021 06:41:18 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 520C761A71 for ; Fri, 1 Oct 2021 06:41:18 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1352125AbhJAGm6 (ORCPT ); Fri, 1 Oct 2021 02:42:58 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:58210 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231165AbhJAGm6 (ORCPT ); Fri, 1 Oct 2021 02:42:58 -0400 Received: from galois.linutronix.de (Galois.linutronix.de [IPv6:2a0a:51c0:0:12e:550::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 6D18EC06176A; Thu, 30 Sep 2021 23:41:14 -0700 (PDT) Date: Fri, 1 Oct 2021 08:41:10 +0200 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020; t=1633070472; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=xK00ctqiWFiU5nGteYW9PbRD7IJFRMc23+AFIc4vmQc=; b=uDNKSqqgL2ktUiJ3xLdIFIBN0zoNRk7sEhoRMIvg1Ovaswt+6mphiYsXLyvHCMey472SFj RAAie+/TScs+MgAHk/nGGzaO2NYr+PXCZ5elb15FW2w3FH4trs8EPZv++NxUjyH4Mv7KmR ajbH0Xu48F1mCVuP9Gqu3qzWGrhyn/mXq237PVZzbF2EB6kGxniNXaZN9WY7qj1BPChGgG n5Abh2vKaIEbOrRqfyQJyWUZ6TG42mSH0/2nvK/Wg68djx8S7NPiqzmj1SX/Y9S/WitpW2 Be0zzAX/wgfJqrxcKRqGlz9MljrKlPsum+/9HI/TgGdsZqtcsKXKuIorEYgpCA== DKIM-Signature: v=1; a=ed25519-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020e; t=1633070472; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=xK00ctqiWFiU5nGteYW9PbRD7IJFRMc23+AFIc4vmQc=; b=eo3244AX3puJEk21YgXyAHizLRxD1mKqWpdZkNJmfPUa2SOyBj4MkGqqqxTl+LkEm1xiaG KjoMMmh+QlP6XiAw== From: Sebastian Andrzej Siewior To: Christoph Hellwig Cc: linux-kernel@vger.kernel.org, linux-scsi@vger.kernel.org, Peter Zijlstra , Thomas Gleixner , Greg Kroah-Hartman , Doug Ledford , Jason Gunthorpe , linux-rdma@vger.kernel.org, Subbu Seetharaman , Ketan Mukadam , Jitendra Bhivare , "James E.J. Bottomley" , "Martin K. Petersen" , "Manoj N. Kumar" , "Matthew R. Ochs" , Uma Krishnan , Brian King , James Smart , Dick Kennedy , Kashyap Desai , Sumit Saxena , Shivasharan S , megaraidlinux.pdl@broadcom.com, Sathya Prakash , Sreekanth Reddy , Suganath Prabu Subramani , MPT-FusionLinux.pdl@broadcom.com Subject: Re: [RFC] Is lib/irq_poll still considered useful? Message-ID: <20211001064110.anckzkd5ymnxvczc@linutronix.de> References: <20210930103754.2128949-1-bigeasy@linutronix.de> <20210930105605.ofyayf3uwk75u25s@linutronix.de> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: Precedence: bulk List-ID: X-Mailing-List: linux-rdma@vger.kernel.org On 2021-10-01 05:24:49 [+0100], Christoph Hellwig wrote: > On Thu, Sep 30, 2021 at 12:56:05PM +0200, Sebastian Andrzej Siewior wrote: > > Is there a reason for the remaining user of irq_poll to keep using it? > > At least for RDMA there are workloads where the latency difference > matters. That's why we added both the irq_poll and workqueue mode > to thew new CQ API a few years ago. Would it work for them to move to threaded interrupts or is the NAPI like behaviour (delay after a while to the next jiffy) the killer feature? Sebastian