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 AB010C7EE26 for ; Mon, 15 May 2023 06:18:26 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233797AbjEOGSZ (ORCPT ); Mon, 15 May 2023 02:18:25 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:50532 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S238619AbjEOGSX (ORCPT ); Mon, 15 May 2023 02:18:23 -0400 Received: from out-40.mta0.migadu.com (out-40.mta0.migadu.com [91.218.175.40]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 583FB1BF9 for ; Sun, 14 May 2023 23:18:20 -0700 (PDT) Date: Mon, 15 May 2023 02:18:14 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.dev; s=key1; t=1684131498; 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=9g4atnH114wwIREvS7FQpq8AT+DoOchnOh70popS5b4=; b=ls7qJyNMnqFIDPENsNB+6BCWOE7+PK2EihntRVfbtXnaMP2H48XTUeJw/pT3TeHklLu2QM oNMGN8jcwYnpeL46T/OXzf4sSOPvZuMY4TzkYy2BLeG3czZwZdLrPejKvonjkBYlvKoUOA EDcEoKkjiz0gJpijRB+sfmNlKdsHcx4= X-Report-Abuse: Please report any abuse attempt to abuse@migadu.com and include these headers. From: Kent Overstreet To: Eric Biggers Cc: Lorenzo Stoakes , Christoph Hellwig , linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org, linux-bcachefs@vger.kernel.org, Kent Overstreet , Andrew Morton , Uladzislau Rezki , linux-mm@kvack.org Subject: Re: [PATCH 07/32] mm: Bring back vmalloc_exec Message-ID: References: <20230510064849.GC1851@quark.localdomain> <20230513015752.GC3033@quark.localdomain> <20230514184325.GB9528@sol.localdomain> <20230515061346.GB15871@sol.localdomain> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20230515061346.GB15871@sol.localdomain> X-Migadu-Flow: FLOW_OUT Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Sun, May 14, 2023 at 11:13:46PM -0700, Eric Biggers wrote: > On Mon, May 15, 2023 at 01:38:51AM -0400, Kent Overstreet wrote: > > On Sun, May 14, 2023 at 11:43:25AM -0700, Eric Biggers wrote: > > > I think it would also help if the generated assembly had the handling of the > > > fields interleaved. To achieve that, it might be necessary to interleave the C > > > code. > > > > No, that has negligable effect on performance - as expected, for an out > > of order processor. < 1% improvement. > > > > It doesn't look like this approach is going to work here. Sadly. > > I'd be glad to take a look at the code you actually tried. It would be helpful > if you actually provided it, instead of just this "I tried it, I'm giving up > now" sort of thing. https://evilpiepirate.org/git/bcachefs.git/log/?h=bkey_unpack > I was also hoping you'd take the time to split this out into a userspace > micro-benchmark program that we could quickly try different approaches on. I don't need to, because I already have this: https://evilpiepirate.org/git/ktest.git/tree/tests/bcachefs/perf.ktest > BTW, even if people are okay with dynamic code generation (which seems > unlikely?), you'll still need a C version for architectures that you haven't > implemented the dynamic code generation for. Excuse me? There already is a C version, and we've been discussing it. Your approach wasn't any faster than the existing C version.