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 vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 7EB98ECAAD1 for ; Tue, 30 Aug 2022 15:24:58 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230439AbiH3PY4 (ORCPT ); Tue, 30 Aug 2022 11:24:56 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:49646 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230437AbiH3PYt (ORCPT ); Tue, 30 Aug 2022 11:24:49 -0400 Received: from dfw.source.kernel.org (dfw.source.kernel.org [IPv6:2604:1380:4641:c500::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 0F79E10D4EC for ; Tue, 30 Aug 2022 08:24:41 -0700 (PDT) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by dfw.source.kernel.org (Postfix) with ESMTPS id 8BB84615E2 for ; Tue, 30 Aug 2022 15:24:40 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 8147DC433C1; Tue, 30 Aug 2022 15:24:39 +0000 (UTC) Authentication-Results: smtp.kernel.org; dkim=pass (1024-bit key) header.d=zx2c4.com header.i=@zx2c4.com header.b="NlF3HcLe" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=zx2c4.com; s=20210105; t=1661873077; 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=xZuNzWTZ1CBdOMWdOgDK3tszHLRIh7WNhf8ToG2ixL4=; b=NlF3HcLeRmVH+Ix2asWoFCOLVkvmlFPlVcfbo5SmKkJKRFEfeIDJ0UCps+Urx6pZYEoFMW cU0cd6P2YEKFHOJAFNTfYby+jsN3/Ac7qN4MQHJc7E8T13C9pkzkoM5AdnsMi7qhZdwRIf /YUguIGju4T4XmOiBpGWHjYhgTs5IHQ= Received: by mail.zx2c4.com (ZX2C4 Mail Server) with ESMTPSA id ce9b7591 (TLSv1.3:TLS_AES_256_GCM_SHA384:256:NO); Tue, 30 Aug 2022 15:24:37 +0000 (UTC) Date: Tue, 30 Aug 2022 11:24:33 -0400 From: "Jason A. Donenfeld" To: Sebastian Andrzej Siewior Cc: linux-kernel@vger.kernel.org, tglx@linutronix.de Subject: Re: [PATCH] random: use raw spinlocks for use on RT Message-ID: References: <20220801142530.133007-1-Jason@zx2c4.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi Sebastian, On Tue, Aug 30, 2022 at 12:13:44PM +0200, Sebastian Andrzej Siewior wrote: > The first patch did so yes. The second simply retried in two secs and > this shouldn't be problematic. This seemed pretty bad too, because now you potentially miss up to 2 seconds of messages AND it adds more complexity. I'm fine with changing things up to accommodate RT, but not when the result is so obviously worse than before. In my tests I can't see any latency difference with using raw spinlocks in random.c. Maybe I'm doing things wrong? But I'm not seeing anything change... Jason