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 B638FCCF9E3 for ; Mon, 10 Nov 2025 16:09:50 +0000 (UTC) Received: from localhost ([::1] helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1vIUSd-0007Xf-5Z; Mon, 10 Nov 2025 11:09:44 -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 1vIUSP-0007RS-8D for qemu-devel@nongnu.org; Mon, 10 Nov 2025 11:09:32 -0500 Received: from us-smtp-delivery-124.mimecast.com ([170.10.133.124]) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1vIUSN-0004PC-Lx for qemu-devel@nongnu.org; Mon, 10 Nov 2025 11:09:29 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1762790967; h=from:from:reply-to:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:cc:mime-version:mime-version: content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=b03e0xLFhHtWm0DRRTwq2gmY2qP55YfD4rSataEJFoY=; b=TjiYW1GWxw0et9e5Ay4B7Fe1RYOIs849DAzAppfqZE5EPZGjICKke+TVVa9IITzt1QQ07q up/Z2pRlfcWnqoBlVnGf30AkyEJ0LyWmVJo7pi9BCmzA73drJlf+wBgvTIwH78RkZMuum/ ipCynTlK/Lec7t0tlaC3Z3rnuTsZ0Ag= 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-376-HtuZOyloOrKineZBCRNw1Q-1; Mon, 10 Nov 2025 11:09:23 -0500 X-MC-Unique: HtuZOyloOrKineZBCRNw1Q-1 X-Mimecast-MFC-AGG-ID: HtuZOyloOrKineZBCRNw1Q_1762790962 Received: from mx-prod-int-08.mail-002.prod.us-west-2.aws.redhat.com (mx-prod-int-08.mail-002.prod.us-west-2.aws.redhat.com [10.30.177.111]) (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 AAED51956089; Mon, 10 Nov 2025 16:09:22 +0000 (UTC) Received: from redhat.com (unknown [10.42.28.62]) by mx-prod-int-08.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTPS id 3EFFB1800451; Mon, 10 Nov 2025 16:09:21 +0000 (UTC) Date: Mon, 10 Nov 2025 16:09:17 +0000 From: Daniel =?utf-8?B?UC4gQmVycmFuZ8Op?= To: Eric Blake Cc: qemu-devel@nongnu.org, qemu-block@nongnu.org, kwolf@redhat.com Subject: Re: [PATCH v2 05/12] qio: Minor optimization when callback function is unchanged Message-ID: References: <20251108230525.3169174-14-eblake@redhat.com> <20251108230525.3169174-19-eblake@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <20251108230525.3169174-19-eblake@redhat.com> User-Agent: Mutt/2.2.14 (2025-02-20) X-Scanned-By: MIMEDefang 3.4.1 on 10.30.177.111 Received-SPF: pass client-ip=170.10.133.124; envelope-from=berrange@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_H3=0.001, RCVD_IN_MSPIKE_WL=0.001, RCVD_IN_VALIDITY_CERTIFIED_BLOCKED=0.001, RCVD_IN_VALIDITY_RPBL_BLOCKED=0.001, SPF_HELO_PASS=-0.001, SPF_PASS=-0.001 autolearn=unavailable autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Reply-To: Daniel =?utf-8?B?UC4gQmVycmFuZ8Op?= Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org On Sat, Nov 08, 2025 at 04:59:26PM -0600, Eric Blake wrote: > In qemu-nbd and other NBD server setups where parallel clients are > supported, it is common that the caller will re-register the same > callback function as long as it has not reached its limit on > simultaneous clients. In that case, there is no need to tear down and > reinstall GSource watches in the GMainContext. > > In practice, all callers currently pass NULL for notify, and no caller > ever changes context across calls (for async uses, either the caller > consistently uses qio_net_listener_set_client_func_full with the same > context, or the caller consistently uses only > qio_net_listener_set_client_func which always uses the global > context); but the time spent checking these two fields in addition to > the more important func and data is still less than the savings of not > churning through extra GSource manipulations when the result will be > unchanged. > > Signed-off-by: Eric Blake > > --- > v2: move later in series, also ensure notify and context are the same > --- > io/net-listener.c | 5 +++++ > 1 file changed, 5 insertions(+) Reviewed-by: Daniel P. Berrangé With regards, Daniel -- |: https://berrange.com -o- https://www.flickr.com/photos/dberrange :| |: https://libvirt.org -o- https://fstop138.berrange.com :| |: https://entangle-photo.org -o- https://www.instagram.com/dberrange :|