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=-3.8 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE, SPF_PASS 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 D60ECC4338F for ; Tue, 3 Aug 2021 07:35:05 +0000 (UTC) Received: from alsa0.perex.cz (alsa0.perex.cz [77.48.224.243]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 95EE560C3E for ; Tue, 3 Aug 2021 07:35:04 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.4.1 mail.kernel.org 95EE560C3E Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=suse.de Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=alsa-project.org Received: from alsa1.perex.cz (alsa1.perex.cz [207.180.221.201]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by alsa0.perex.cz (Postfix) with ESMTPS id 32AA616FF; Tue, 3 Aug 2021 09:34:13 +0200 (CEST) DKIM-Filter: OpenDKIM Filter v2.11.0 alsa0.perex.cz 32AA616FF DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=alsa-project.org; s=default; t=1627976103; bh=ibpX4zPYipdXCW9DQYQKHt6h0N7Zbh0kgpLMnA+5TpE=; h=Date:From:To:Subject:In-Reply-To:References:Cc:List-Id: List-Unsubscribe:List-Archive:List-Post:List-Help:List-Subscribe: From; b=ggwQDqhvy7LpM1JTy+LNTSfb7OPaU1dSiSXD5BNYPfm/v4aovx3GBH5k9dsuvGDVg o2R+SNBjsVoXWdROrAvGQZF8z/5f2C2SE2PTXB/DKVtOWhwuAt+zkKyJKFEpES4j9X pzXOPIIHbg7xebzQkr667qACunBTMLFxSswceoec= Received: from alsa1.perex.cz (localhost.localdomain [127.0.0.1]) by alsa1.perex.cz (Postfix) with ESMTP id B61ABF80095; Tue, 3 Aug 2021 09:34:12 +0200 (CEST) Received: by alsa1.perex.cz (Postfix, from userid 50401) id C1AF4F802E8; Tue, 3 Aug 2021 09:34:10 +0200 (CEST) Received: from smtp-out2.suse.de (smtp-out2.suse.de [195.135.220.29]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by alsa1.perex.cz (Postfix) with ESMTPS id 7B86AF80095 for ; Tue, 3 Aug 2021 09:34:07 +0200 (CEST) DKIM-Filter: OpenDKIM Filter v2.11.0 alsa1.perex.cz 7B86AF80095 Authentication-Results: alsa1.perex.cz; dkim=pass (1024-bit key) header.d=suse.de header.i=@suse.de header.b="cViNMVRu"; dkim=permerror (0-bit key) header.d=suse.de header.i=@suse.de header.b="8yGylLFG" Received: from relay2.suse.de (relay2.suse.de [149.44.160.134]) by smtp-out2.suse.de (Postfix) with ESMTP id 0E1F92009F; Tue, 3 Aug 2021 07:34:06 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=suse.de; s=susede2_rsa; t=1627976046; h=from:from:reply-to: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=rXdJtGLDQ+wBCmobp3Y0JiVh7UhX3DxLaqDqHYPgrck=; b=cViNMVRuHdVxqGe12qDQLe2n2XIbj/qmE0buY8vEzEdQtd3QmNAPX/hxwG7+dqxMoNsuN/ r2dYW3LosKneoLrZZTfCsaV3tjusZfghjf3CjI/vcmzN2w49dPc6Daq88jje94NPDpQLba myqu6Fx/B5w6T34k3UFU9LaTBzL3lIc= DKIM-Signature: v=1; a=ed25519-sha256; c=relaxed/relaxed; d=suse.de; s=susede2_ed25519; t=1627976046; h=from:from:reply-to: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=rXdJtGLDQ+wBCmobp3Y0JiVh7UhX3DxLaqDqHYPgrck=; b=8yGylLFGiyPpN7VTmEcpR1TjM6PLed1WYxfJYQswLr2cd2UGYER7u9IYIOMbeG1mJgE7hn GM8KKFZ4laW4YmBA== Received: from alsa1.suse.de (alsa1.suse.de [10.160.4.42]) by relay2.suse.de (Postfix) with ESMTP id 038F6A3BCA; Tue, 3 Aug 2021 07:34:06 +0000 (UTC) Date: Tue, 03 Aug 2021 09:34:05 +0200 Message-ID: From: Takashi Iwai To: Giuliano Zannetti - ART S.p.A. Subject: Re: I: dmix optimization In-Reply-To: References: User-Agent: Wanderlust/2.15.9 (Almost Unreal) SEMI/1.14.6 (Maruoka) FLIM/1.14.9 (=?UTF-8?B?R29qxY0=?=) APEL/10.8 Emacs/25.3 (x86_64-suse-linux-gnu) MULE/6.0 (HANACHIRUSATO) MIME-Version: 1.0 (generated by SEMI 1.14.6 - "Maruoka") Content-Type: text/plain; charset=US-ASCII Cc: "alsa-devel@alsa-project.org" , "tiwai@suse.com" X-BeenThere: alsa-devel@alsa-project.org X-Mailman-Version: 2.1.15 Precedence: list List-Id: "Alsa-devel mailing list for ALSA developers - http://www.alsa-project.org" List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: alsa-devel-bounces@alsa-project.org Sender: "Alsa-devel" On Tue, 03 Aug 2021 09:26:38 +0200, Giuliano Zannetti - ART S.p.A. wrote: > (snip) > Could it be possible check for the first sample of the period only, as > reported in the code below? No, unfortunately your suggested optimization won't work reliably, I'm afraid. Each application may write samples partially, not always in period size. Also, the hardware may clear the buffer right after the hwptr is updated, and again, it's not always in period size. So, just checking the first sample doesn't guarantee the rest period size is also zero or non-zero. thanks, Takashi