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=-0.8 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,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 95926C4321A for ; Sat, 29 Jun 2019 17:23:29 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 6FF5020665 for ; Sat, 29 Jun 2019 17:23:29 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=lkcl.net header.i=@lkcl.net header.b="RKPqwaFS" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726864AbfF2RXY (ORCPT ); Sat, 29 Jun 2019 13:23:24 -0400 Received: from lkcl.net ([217.147.94.29]:42415 "EHLO lkcl.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726837AbfF2RXY (ORCPT ); Sat, 29 Jun 2019 13:23:24 -0400 X-Greylist: delayed 2287 seconds by postgrey-1.27 at vger.kernel.org; Sat, 29 Jun 2019 13:23:23 EDT DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lkcl.net; s=201607131; h=Content-Type:Cc:To:Subject:Message-ID:Date:From:MIME-Version; bh=s/sTi+hASQyPaQRLVOOh9ET0ya6bVtdjcUHl64yNEJw=; b=RKPqwaFSFIFMxHCBw4GHqMY/1g7FEz7d0qo3eSy8ZtoC7DxmMt9BSLvCKb5oZ9PmwTer3bGW1sgc1Yo+fJXcBI3Q4RSrGfZqhPAF4G0BKV3t6bwaoktseUAjQmbGjVlLm2BGnRSsPcHX9jwNWu4IPsi9pxRRoghqesCT8zjPfkI=; Received: from mail-lj1-f176.google.com ([209.85.208.176]) by lkcl.net with esmtpsa (TLS1.2:ECDHE_RSA_AES_128_GCM_SHA256:128) (Exim 4.84_2) (envelope-from ) id 1hhGTS-0008P0-Rf; Sat, 29 Jun 2019 16:45:14 +0000 Received: by mail-lj1-f176.google.com with SMTP id t28so8909104lje.9; Sat, 29 Jun 2019 09:44:59 -0700 (PDT) X-Gm-Message-State: APjAAAXeYxu9TidZ+kwM0+MFIZCL45e0dxzD9Jul0xAThrxOt+UTUiD6 D82ieLKUDH2aL1MtJeSx2+FeZEFPsrSK6HnZLHs= X-Google-Smtp-Source: APXvYqyT3rBGT+21WQD3pj3PIsLlCJsWc/KxmRIzx71GAXDRlfDfgfqr73eWhFqOZ/B2TWPMlCqEQW13yM2ujHPob5E= X-Received: by 2002:a2e:94cb:: with SMTP id r11mr8821456ljh.212.1561826376022; Sat, 29 Jun 2019 09:39:36 -0700 (PDT) MIME-Version: 1.0 From: Luke Kenneth Casson Leighton Date: Sat, 29 Jun 2019 17:39:24 +0100 X-Gmail-Original-Message-ID: Message-ID: Subject: Re: bcachefs status update (it's done cooking; let's get this sucker merged) To: torvalds@linux-foundation.org Cc: akpm@linux-foundation.org, axboe@kernel.dk, darrick.wong@oracle.com, david@fromorbit.com, dchinner@redhat.com, josef@toxicpanda.com, kent.overstreet@gmail.com, linux-bcache@vger.kernel.org, linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, peterz@infradead.org, tj@kernel.org, viro@zeniv.linux.org.uk, zach.brown@ni.com Content-Type: text/plain; charset="UTF-8" Sender: linux-fsdevel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-fsdevel@vger.kernel.org hey linus, you made news again, all blown up and pointless again. you're doing great: you're being honest. remember the offer i made to put you in touch with my friend. anecdotal story: andrew tridgell worked on the fujitsu sparc supercomputer a couple decades ago: it had a really weird DMA ring bus. * memory-to-memory copy (in the same core) was 10mbytes/sec * DMA memory-to-memory copy (in the same core) was 20mbytes/sec * memory-memory copy (across the ring bus i.e. to another machine) was 100mbytes/sec * DMA memory-memory copy (across the ring bus) was *200* mbytes/sec. when andrew tried asking people, "hey everyone, we need a filesystem that can work really well on this fast parallel system", he had to continuously fend off "i got a great idea for in-core memory-to-memory cacheing!!!!" suggestions, because they *just would never work*. the point being: caches aren't always "fast". /salutes. l.