From owner-svn-src-head@freebsd.org Thu Nov 29 19:28:02 2018 Return-Path: Delivered-To: svn-src-head@mailman.ysv.freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2610:1c1:1:606c::19:1]) by mailman.ysv.freebsd.org (Postfix) with ESMTP id 6ECF4114A879; Thu, 29 Nov 2018 19:28:02 +0000 (UTC) (envelope-from sobomax@FreeBSD.org) Received: from mxrelay.nyi.freebsd.org (mxrelay.nyi.freebsd.org [IPv6:2610:1c1:1:606c::19:3]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (Client CN "mxrelay.nyi.freebsd.org", Issuer "Let's Encrypt Authority X3" (verified OK)) by mx1.freebsd.org (Postfix) with ESMTPS id 117237F26E; Thu, 29 Nov 2018 19:28:02 +0000 (UTC) (envelope-from sobomax@FreeBSD.org) Received: from repo.freebsd.org (repo.freebsd.org [IPv6:2610:1c1:1:6068::e6a:0]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (Client did not present a certificate) by mxrelay.nyi.freebsd.org (Postfix) with ESMTPS id E21521DE17; Thu, 29 Nov 2018 19:28:01 +0000 (UTC) (envelope-from sobomax@FreeBSD.org) Received: from repo.freebsd.org ([127.0.1.37]) by repo.freebsd.org (8.15.2/8.15.2) with ESMTP id wATJS1IO021890; Thu, 29 Nov 2018 19:28:01 GMT (envelope-from sobomax@FreeBSD.org) Received: (from sobomax@localhost) by repo.freebsd.org (8.15.2/8.15.2/Submit) id wATJS1mP021888; Thu, 29 Nov 2018 19:28:01 GMT (envelope-from sobomax@FreeBSD.org) Message-Id: <201811291928.wATJS1mP021888@repo.freebsd.org> X-Authentication-Warning: repo.freebsd.org: sobomax set sender to sobomax@FreeBSD.org using -f From: Maxim Sobolev Date: Thu, 29 Nov 2018 19:28:01 +0000 (UTC) To: src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-head@freebsd.org Subject: svn commit: r341257 - head/bin/dd X-SVN-Group: head X-SVN-Commit-Author: sobomax X-SVN-Commit-Paths: head/bin/dd X-SVN-Commit-Revision: 341257 X-SVN-Commit-Repository: base MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit X-Rspamd-Queue-Id: 117237F26E X-Spamd-Result: default: False [0.57 / 15.00]; local_wl_from(0.00)[FreeBSD.org]; NEURAL_SPAM_LONG(0.31)[0.307,0]; NEURAL_SPAM_SHORT(0.01)[0.007,0]; NEURAL_SPAM_MEDIUM(0.26)[0.256,0]; ASN(0.00)[asn:11403, ipnet:2610:1c1:1::/48, country:US] X-Rspamd-Server: mx1.freebsd.org X-BeenThere: svn-src-head@freebsd.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: SVN commit messages for the src tree for head/-current List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Thu, 29 Nov 2018 19:28:02 -0000 Author: sobomax Date: Thu Nov 29 19:28:01 2018 New Revision: 341257 URL: https://svnweb.freebsd.org/changeset/base/341257 Log: Replace hand-crafted naive byte-by-byte zero block detection routine with macro based around memcmp(). The latter is expected to be some 8 times faster on a modern 64-bit architectures. In practice, throughput of doing conv=sparse from /dev/zero to /dev/null went up some 5-fold here from 1.9GB/sec to 9.7GB/sec with this change (bs=128k). MFC after: 2 weeks Modified: head/bin/dd/dd.c head/bin/dd/dd.h Modified: head/bin/dd/dd.c ============================================================================== --- head/bin/dd/dd.c Thu Nov 29 19:13:10 2018 (r341256) +++ head/bin/dd/dd.c Thu Nov 29 19:28:01 2018 (r341257) @@ -511,7 +511,7 @@ void dd_out(int force) { u_char *outp; - size_t cnt, i, n; + size_t cnt, n; ssize_t nw; static int warned; int sparse; @@ -544,12 +544,8 @@ dd_out(int force) do { sparse = 0; if (ddflags & C_SPARSE) { - sparse = 1; /* Is buffer sparse? */ - for (i = 0; i < cnt; i++) - if (outp[i] != 0) { - sparse = 0; - break; - } + /* Is buffer sparse? */ + sparse = BISZERO(outp, cnt); } if (sparse && !force) { pending += cnt; Modified: head/bin/dd/dd.h ============================================================================== --- head/bin/dd/dd.h Thu Nov 29 19:13:10 2018 (r341256) +++ head/bin/dd/dd.h Thu Nov 29 19:28:01 2018 (r341257) @@ -103,3 +103,7 @@ typedef struct { #define C_PROGRESS 0x40000000 #define C_PARITY (C_PAREVEN | C_PARODD | C_PARNONE | C_PARSET) + +#define BISZERO(p, s) ((s) > 0 && *((const char *)p) == 0 && !memcmp( \ + (const void *)(p), (const void *) \ + ((const char *)p + 1), (s) - 1))