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 lists.gnu.org (lists.gnu.org [209.51.188.17]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 68527D4A609 for ; Fri, 16 Jan 2026 08:20:23 +0000 (UTC) Received: from localhost ([::1] helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1vgf3s-0006D2-1P; Fri, 16 Jan 2026 03:20:04 -0500 Received: from eggs.gnu.org ([2001:470:142:3::10]) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1vgf3q-0006Cc-IP for qemu-devel@nongnu.org; Fri, 16 Jan 2026 03:20:02 -0500 Received: from us-smtp-delivery-124.mimecast.com ([170.10.129.124]) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1vgf3o-0000jd-SU for qemu-devel@nongnu.org; Fri, 16 Jan 2026 03:20:02 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1768551600; 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=4y58swJ8SEaUb3Okk1L6cXS1m2gBdcM5UQ6hxS9jcig=; b=au9cXuR9RcDj/oVfTzY42Fs8UEO3fe2jClTpvhG8XS6RR3aA3Y8LxmM/bQpkjHaqIAU8kT 5JsmDAR+5NLMYVdaGE1UlhdlK3gx867vkMmRKBemvGeMqOVN6G0wiCl8xLpMv5iyZ/qxR5 +/IgXtePrYIa7P1cD4tUVWZQGLbQI/s= Received: from mx-prod-mc-05.mail-002.prod.us-west-2.aws.redhat.com (ec2-54-186-198-63.us-west-2.compute.amazonaws.com [54.186.198.63]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_256_GCM_SHA384) id us-mta-121-VLaqVavPMjyoUHEpVurMIQ-1; Fri, 16 Jan 2026 03:19:57 -0500 X-MC-Unique: VLaqVavPMjyoUHEpVurMIQ-1 X-Mimecast-MFC-AGG-ID: VLaqVavPMjyoUHEpVurMIQ_1768551596 Received: from mx-prod-int-03.mail-002.prod.us-west-2.aws.redhat.com (mx-prod-int-03.mail-002.prod.us-west-2.aws.redhat.com [10.30.177.12]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits) server-digest SHA256) (No client certificate requested) by mx-prod-mc-05.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTPS id DE9A019560B3; Fri, 16 Jan 2026 08:19:55 +0000 (UTC) Received: from blackfin.pond.sub.org (unknown [10.45.242.32]) by mx-prod-int-03.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTPS id 142201955F67; Fri, 16 Jan 2026 08:19:54 +0000 (UTC) Received: by blackfin.pond.sub.org (Postfix, from userid 1000) id 79B1621E692D; Fri, 16 Jan 2026 09:19:52 +0100 (CET) From: Markus Armbruster To: Halil Pasic Cc: JAEHOON KIM , qemu-devel@nongnu.org, qemu-block@nongnu.org, pbonzini@redhat.com, stefanha@redhat.com, fam@euphon.net, eblake@redhat.com, berrange@redhat.com, eduardo@habkost.net, dave@treblig.org, sw@weilnetz.de, devel@lists.libvirt.org Subject: Re: [PATCH RFC v1 3/3] qapi/iothread: introduce poll-weight parameter for aio-poll In-Reply-To: <20260115110532.27cb1516.pasic@linux.ibm.com> (Halil Pasic's message of "Thu, 15 Jan 2026 11:05:32 +0100") References: <20260113174824.464720-1-jhkim@linux.ibm.com> <20260113174824.464720-4-jhkim@linux.ibm.com> <87qzrs4oud.fsf@pond.sub.org> <87ikd3xrkc.fsf@pond.sub.org> <20260115110532.27cb1516.pasic@linux.ibm.com> Date: Fri, 16 Jan 2026 09:19:52 +0100 Message-ID: <87sec6rmtz.fsf@pond.sub.org> User-Agent: Gnus/5.13 (Gnus v5.13) MIME-Version: 1.0 Content-Type: text/plain X-Scanned-By: MIMEDefang 3.0 on 10.30.177.12 Received-SPF: pass client-ip=170.10.129.124; envelope-from=armbru@redhat.com; helo=us-smtp-delivery-124.mimecast.com X-Spam_score_int: -20 X-Spam_score: -2.1 X-Spam_bar: -- X-Spam_report: (-2.1 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.001, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_NONE=-0.0001, RCVD_IN_MSPIKE_H2=0.001, RCVD_IN_VALIDITY_RPBL_BLOCKED=0.001, RCVD_IN_VALIDITY_SAFE_BLOCKED=0.001, SPF_HELO_PASS=-0.001, SPF_PASS=-0.001 autolearn=ham autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: qemu development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Halil Pasic writes: > On Thu, 15 Jan 2026 08:28:51 +0100 > Markus Armbruster wrote: > >> I understand that you're mirroring how @poll-grow and @poll-shrink work, >> but let's ignore that for a minute. >> >> Compare four possible interfaces: >> >> 1. Optional @poll-weight defaults to 2. Values <= 0 are rejected. >> >> 2. Optional @poll-weight defaults to 2. Value 0 is replaced by the >> default value 2. Values < 0 are rejected. >> >> 3. Optional @poll-weight defaults to 0. Values < 0 are rejected. Value >> 0 makes the system pick a value, namely 2. >> >> 4. Optional @poll-weight defaults to 0. Values < 0 are rejected. Value >> 0 makes the system pick a value. It currently picks 2. >> >> The difference between 3. and 4. is that 3. makes "system picks 2" part >> of the contract, while 4. doesn't. >> >> 1. is the simplest. Is 2.'s additional complexity worthwhile? 3.'s? >> 4.'s? > > Isn't there more options? Like Yes :) > 5. Optional @poll-weight defaults to system-default. Value 0 is replaced > by the system pick the system default value. Currently the system default > value is 2. Values < 0 are rejected. > > That would mean: > * current value inspectable > * system default not part of the interface contract > * interface offers a "please go back to value not user specified: > operation > > BTW I like your approach with explicitly listing and evaluating the > options a lot! Thanks!