From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mx0b-001ae601.pphosted.com (mx0b-001ae601.pphosted.com [67.231.152.168]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id D1BB218DB09; Tue, 25 Feb 2025 16:23:07 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=67.231.152.168 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1740500589; cv=none; b=sw6zOLbybkkCwDR7/w+rALwQ75P+uk+TPWkmXVZXYf7PfNsKYoFA+nRXCh1v8hZ5T6N2lnTrqznugfpOXSzUxwOMyIeJd+kgotyi+8fY09Cx+z+PSkLdVz94gaDWXle7sNMDwt0frRC7ebgBSYznNUqokqKG/deM/ve5dzWpNNU= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1740500589; c=relaxed/simple; bh=njrjcyJPge/h5dZ0Uk9mlzgjkTwBWMZIka8AEb5N860=; h=Message-ID:Date:MIME-Version:Subject:To:CC:References:From: In-Reply-To:Content-Type; b=GbgGnUrDwK5nb0c5bqpHBu69NMcrpkATuDfS2o0EX0IytPWGBsjLwGO6A7fzrxQ5I6zd4ivhJsS88TtIvQB8LRL4GWl24zkgMjf8k7C3xmiKDk0DtUIIi6RvVpjIrKzm9JwsIz1tJVYaUyvC4FrvrNEiJ0xU42gtkrvpApMp1kk= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=opensource.cirrus.com; spf=pass smtp.mailfrom=opensource.cirrus.com; dkim=pass (2048-bit key) header.d=cirrus.com header.i=@cirrus.com header.b=FSosTLsX; arc=none smtp.client-ip=67.231.152.168 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=opensource.cirrus.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=opensource.cirrus.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=cirrus.com header.i=@cirrus.com header.b="FSosTLsX" Received: from pps.filterd (m0077474.ppops.net [127.0.0.1]) by mx0b-001ae601.pphosted.com (8.18.1.2/8.18.1.2) with ESMTP id 51P4Sj4J005888; Tue, 25 Feb 2025 10:22:51 -0600 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=cirrus.com; h=cc :content-transfer-encoding:content-type:date:from:in-reply-to :message-id:mime-version:references:subject:to; s= PODMain02222019; bh=zAI3cVRk/zYi3skFlAy3pn2KRdgiwLHEQmJNZuB9oxk=; b= FSosTLsXWSz3xt/uyytE7j4HYXRn7cnueCJJlG3Fz1gLTrWIa6WfkWPPEKKiMpyZ KJhN7zfNrvtHm88sb7maIo25jSMWUsed5irLQjKcAP2ZdgfKn/YDk64AMPA9bx8S Nd73k/W0vATjgWwAwRnKYPuFUzArD81YSyUrl8UQmYvSQ9ONjCjAzz+ly9+VWH0P pwGXHGEdMMOG4Zu+g6941lRpeu2Ftr5l5d/vmxIl6/ZUAn679TbdHfHeTr2Pgtwa 0qs8d3ZaDqsDEMDU1J1BcWLTNnS1DozHDsocYPQVVuIpNSj9uwsvjJpdX+CoiH0d eP8dVM+lhONE520g0nFa5g== Received: from ediex02.ad.cirrus.com ([84.19.233.68]) by mx0b-001ae601.pphosted.com (PPS) with ESMTPS id 44ybvpy85w-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Tue, 25 Feb 2025 10:22:51 -0600 (CST) Received: from ediex01.ad.cirrus.com (198.61.84.80) by ediex02.ad.cirrus.com (198.61.84.81) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.2.1544.14; Tue, 25 Feb 2025 16:22:49 +0000 Received: from ediswmail9.ad.cirrus.com (198.61.86.93) by anon-ediex01.ad.cirrus.com (198.61.84.80) with Microsoft SMTP Server id 15.2.1544.14 via Frontend Transport; Tue, 25 Feb 2025 16:22:49 +0000 Received: from [198.90.208.18] (ediswws06.ad.cirrus.com [198.90.208.18]) by ediswmail9.ad.cirrus.com (Postfix) with ESMTP id B6A7782025A; Tue, 25 Feb 2025 16:22:49 +0000 (UTC) Message-ID: Date: Tue, 25 Feb 2025 16:22:49 +0000 Precedence: bulk X-Mailing-List: linux-sound@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH 1/2] firmware: cs_dsp: Remove async regmap writes To: Mark Brown CC: , , , References: <20250225131843.113752-1-rf@opensource.cirrus.com> <20250225131843.113752-2-rf@opensource.cirrus.com> Content-Language: en-GB From: Richard Fitzgerald In-Reply-To: Content-Type: text/plain; charset="UTF-8"; format=flowed Content-Transfer-Encoding: 7bit X-Authority-Analysis: v=2.4 cv=HoCMG1TS c=1 sm=1 tr=0 ts=67bdee5b cx=c_pps a=uGhh+3tQvKmCLpEUO+DX4w==:117 a=uGhh+3tQvKmCLpEUO+DX4w==:17 a=IkcTkHD0fZMA:10 a=T2h4t0Lz3GQA:10 a=l4K2p79tHvvzm6wvxRIA:9 a=QEXdDO2ut3YA:10 X-Proofpoint-GUID: 8USdONOCFGdy5sACm-iHsmNeeJuWcyGi X-Proofpoint-ORIG-GUID: 8USdONOCFGdy5sACm-iHsmNeeJuWcyGi X-Proofpoint-Spam-Reason: safe On 25/02/2025 3:15 pm, Mark Brown wrote: > On Tue, Feb 25, 2025 at 01:18:42PM +0000, Richard Fitzgerald wrote: > >> The async writes are a 12-year-old workaround for inefficiency of >> synchronous writes in the SPI subsystem. The SPI subsystem has since >> been changed to avoid the overheads, so this workaround should not be >> necessary. > > That wasn't really the issue, it was that on systems with low numbers of > slower cores (especially single core but there were some dual core > systems too) there was a surprisingly low threashold where it was useful > to overlap the marshalling of data to send to the device with > transmitting already marshalled data. SMP adds locking requirements > which loose a lot of the gains, and it's controller dependent where the > cuttoff points for interrupts and/or DMA are. Ok. It was a very long time ago. Do you want a V2 with a commit message that doesn't libel the SPI framework? FWIW switching to sync write reduced the download of small amp firmware by 200ms on a 1.67MHz SPI bus.