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_INVALID, DKIM_SIGNED,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE, SPF_PASS,URIBL_BLOCKED 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 33F0AC433E1 for ; Thu, 23 Jul 2020 18:25:18 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 133D320792 for ; Thu, 23 Jul 2020 18:25:18 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (1024-bit key) header.d=mg.codeaurora.org header.i=@mg.codeaurora.org header.b="AngoQR5+" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727809AbgGWSZQ (ORCPT ); Thu, 23 Jul 2020 14:25:16 -0400 Received: from m43-7.mailgun.net ([69.72.43.7]:64088 "EHLO m43-7.mailgun.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726617AbgGWSZQ (ORCPT ); Thu, 23 Jul 2020 14:25:16 -0400 DKIM-Signature: a=rsa-sha256; v=1; c=relaxed/relaxed; d=mg.codeaurora.org; q=dns/txt; s=smtp; t=1595528715; h=Content-Transfer-Encoding: Content-Type: MIME-Version: Message-ID: Date: Subject: In-Reply-To: References: Cc: To: From: Sender; bh=yAfJG1ZM4LmfNVZaxnZ0GMv0GxwURX4mJ3TXKqKYdGE=; b=AngoQR5+YzZ6kKQP/BCWEF1Sh0Xd3egoAphORlihddjojj92/d+oNHfTX3OVBt0eLiZUbotC JQuKmdQvV8GENSf1fQHNGbznOy+hUn0iXE5FWylMLiehGX4mhTXK73WoJTIg/7n1rPliepwE pj/DZCSYx/Tgsv9XijJE3/I/m5A= X-Mailgun-Sending-Ip: 69.72.43.7 X-Mailgun-Sid: WyJiZjI2MiIsICJuZXRkZXZAdmdlci5rZXJuZWwub3JnIiwgImJlOWU0YSJd Received: from smtp.codeaurora.org (ec2-35-166-182-171.us-west-2.compute.amazonaws.com [35.166.182.171]) by smtp-out-n01.prod.us-west-2.postgun.com with SMTP id 5f19d60a5b75bcda60cbde6b (version=TLS1.2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256); Thu, 23 Jul 2020 18:25:14 GMT Received: by smtp.codeaurora.org (Postfix, from userid 1001) id 1EFAAC433CA; Thu, 23 Jul 2020 18:25:14 +0000 (UTC) Received: from Pillair (unknown [183.83.71.149]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) (Authenticated sender: pillair) by smtp.codeaurora.org (Postfix) with ESMTPSA id B12BFC433C6; Thu, 23 Jul 2020 18:25:09 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 smtp.codeaurora.org B12BFC433C6 Authentication-Results: aws-us-west-2-caf-mail-1.web.codeaurora.org; dmarc=none (p=none dis=none) header.from=codeaurora.org Authentication-Results: aws-us-west-2-caf-mail-1.web.codeaurora.org; spf=none smtp.mailfrom=pillair@codeaurora.org From: "Rakesh Pillai" To: "'Rajkumar Manoharan'" Cc: , , , , , , , , , , References: <1595351666-28193-1-git-send-email-pillair@codeaurora.org> <1595351666-28193-3-git-send-email-pillair@codeaurora.org> <13573549c277b34d4c87c471ff1a7060@codeaurora.org> In-Reply-To: <13573549c277b34d4c87c471ff1a7060@codeaurora.org> Subject: RE: [RFC 2/7] ath10k: Add support to process rx packet in thread Date: Thu, 23 Jul 2020 23:55:06 +0530 Message-ID: <003001d6611e$9afa0cc0$d0ee2640$@codeaurora.org> MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit X-Mailer: Microsoft Outlook 16.0 Thread-Index: AQG1Bu1FBYi7G1oVhHY/01uT1gSslwH2O/GCAtCmWRqpMfdhsA== Content-Language: en-us Sender: netdev-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org > -----Original Message----- > From: Rajkumar Manoharan > Sent: Wednesday, July 22, 2020 3:23 AM > To: Rakesh Pillai > Cc: ath10k@lists.infradead.org; linux-wireless@vger.kernel.org; linux- > kernel@vger.kernel.org; kvalo@codeaurora.org; johannes@sipsolutions.net; > davem@davemloft.net; kuba@kernel.org; netdev@vger.kernel.org; > dianders@chromium.org; evgreen@chromium.org; linux-wireless- > owner@vger.kernel.org > Subject: Re: [RFC 2/7] ath10k: Add support to process rx packet in thread > > On 2020-07-21 10:14, Rakesh Pillai wrote: > > NAPI instance gets scheduled on a CPU core on which > > the IRQ was triggered. The processing of rx packets > > can be CPU intensive and since NAPI cannot be moved > > to a different CPU core, to get better performance, > > its better to move the gist of rx packet processing > > in a high priority thread. > > > > Add the init/deinit part for a thread to process the > > receive packets. > > > IMHO this defeat the whole purpose of NAPI. Originally in ath10k > irq processing happened in tasklet (high priority) context which in > turn push more data to net core even though net is unable to process > driver data as both happen in different context (fast producer - slow > consumer) > issue. Why can't CPU governor schedule the interrupts in less loaded CPU > core? > Otherwise you can play with different RPS and affinity settings to meet > your > requirement. > > IMO introducing high priority tasklets/threads is not viable solution. Hi Rajkumar, In linux, the IRQs are directed to the first core which is booted. I see that all the IRQs are getting routed to CORE0 even if its heavily loaded. IRQ and NAPI are not under the scheduler's control, since it cannot be moved. NAPI is scheduled only on the same core as IRQ. But a thread can be moved around by the scheduler based on the CPU load. This is the reason I went ahead with using thread. Affinity settings are static, and cannot be done runtime without any downstream userspace entity. > > -Rajkumar