From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on dcvr.yhbt.net X-Spam-Level: X-Spam-ASN: AS31976 209.132.180.0/23 X-Spam-Status: No, score=-3.6 required=3.0 tests=AWL,BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,RCVD_IN_DNSWL_HI,RP_MATCHES_RCVD shortcircuit=no autolearn=ham autolearn_force=no version=3.4.0 Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by dcvr.yhbt.net (Postfix) with ESMTP id 394801FCA0 for ; Tue, 28 Mar 2017 15:31:50 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751590AbdC1PbY (ORCPT ); Tue, 28 Mar 2017 11:31:24 -0400 Received: from siwi.pair.com ([209.68.5.199]:62781 "EHLO siwi.pair.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751410AbdC1PbX (ORCPT ); Tue, 28 Mar 2017 11:31:23 -0400 Received: from [10.160.98.126] (unknown [167.220.148.155]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by siwi.pair.com (Postfix) with ESMTPSA id C953484673; Tue, 28 Mar 2017 11:30:47 -0400 (EDT) Subject: Re: [PATCH v2 0/2] read-cache: call verify_hdr() in a background thread To: Jeff King References: <1490648979-49580-1-git-send-email-git@jeffhostetler.com> <20170327224505.ngp2gel3yvqcjrhw@sigill.intra.peff.net> Cc: git@vger.kernel.org, gitster@pobox.com, Jeff Hostetler From: Jeff Hostetler Message-ID: Date: Tue, 28 Mar 2017 11:30:47 -0400 User-Agent: Mozilla/5.0 (Windows NT 10.0; WOW64; rv:45.0) Gecko/20100101 Thunderbird/45.8.0 MIME-Version: 1.0 In-Reply-To: <20170327224505.ngp2gel3yvqcjrhw@sigill.intra.peff.net> Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 7bit Sender: git-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: git@vger.kernel.org On 3/27/2017 6:45 PM, Jeff King wrote: > On Mon, Mar 27, 2017 at 09:09:37PM +0000, git@jeffhostetler.com wrote: > >> From: Jeff Hostetler >> >> Version 2 of this patch series simplifies this to just >> turn off the hash verification. Independent comments >> from Linus and Peff suggested that we could just turn >> this off and not worry about it. So I've updated this >> patch to do that. I added a global variable to allow >> the original code path to be used. I also added a >> t/helper command to demonstrate the differences. >> >> On the Linux repo, the effect is rather trivial: >> >> $ ~/work/gfw/t/helper/test-skip-verify-index -c 3 >> 0.029884 0 [cache_nr 57994] >> 0.031035 0 [cache_nr 57994] >> 0.024308 0 [cache_nr 57994] >> 0.028409 0 avg >> 0.018359 1 [cache_nr 57994] >> 0.017025 1 [cache_nr 57994] >> 0.011087 1 [cache_nr 57994] >> 0.015490 1 avg >> >> On my Windows source tree (450MB index), I'm seeing a >> savings of 0.6 seconds -- read_index() went from 1.2 to 0.6 >> seconds. > > Very satisfying. I assume that was with OpenSSL as the SHA-1 > implementation (sha1dc would have been much slower on 450MB, I think). > > -Peff > Yes, this was with the OpenSSL SHA-1 code in a GfW build. I haven't played with the sha1dc code yet. $ $/work/gh_gfw/t/helper/test-skip-verify-index.exe -c 5 1.276485 0 [cache_nr 3077831] 1.261164 0 [cache_nr 3077831] 1.256012 0 [cache_nr 3077831] 1.261411 0 [cache_nr 3077831] 1.266174 0 [cache_nr 3077831] 1.264249 0 avg 0.672057 1 [cache_nr 3077831] 0.666968 1 [cache_nr 3077831] 0.668725 1 [cache_nr 3077831] 0.675879 1 [cache_nr 3077831] 0.670213 1 [cache_nr 3077831] 0.670768 1 avg Jeff