Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S272636AbTHPIUJ (ORCPT ); Sat, 16 Aug 2003 04:20:09 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S272639AbTHPIUI (ORCPT ); Sat, 16 Aug 2003 04:20:08 -0400 Received: from [212.209.10.216] ([212.209.10.216]:4802 "EHLO krynn.se.axis.com") by vger.kernel.org with ESMTP id S272636AbTHPIUD (ORCPT ); Sat, 16 Aug 2003 04:20:03 -0400 Message-ID: From: Peter Kjellerstedt To: "'Timothy Miller'" Cc: "'Willy Tarreau'" , linux-kernel mailing list Subject: RE: generic strncpy - off-by-one error Date: Sat, 16 Aug 2003 10:15:14 +0200 MIME-Version: 1.0 X-Mailer: Internet Mail Service (5.5.2653.19) Content-Type: text/plain Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1896 Lines: 74 > -----Original Message----- > From: Timothy Miller [mailto:miller@techsource.com] > Sent: Friday, August 15, 2003 19:52 > To: Peter Kjellerstedt > Cc: 'Willy Tarreau'; linux-kernel mailing list > Subject: Re: generic strncpy - off-by-one error > > Peter Kjellerstedt wrote: > > Timothy's 3.125003 6.128571 9.147905 33.325337 > > Which of mine did you test? The one with the single-byte > fill, or the one with the multiple fill loops that does > words for the bulk of the fills? Stupid me. I only tested the single byte fill version. > With some minor tweaks to eliminate compiler stupidity which compares > against -1, that might win on the fill phase. No? Here are the numbers for my for loop version and your multi byte fill version for CRIS: For loops 2.867568 5.620561 8.128734 28.286289 Multi byte fill 2.868031 5.670782 6.312027 11.336015 And here are the numbers for my P4: For loops 3.060262 5.927378 8.796814 30.659818 Multi byte fill 3.126607 5.898459 7.096685 13.135379 So there is no doubt that the multi byte version is a clear winner (which was expected, I suppose). Here is the code that I used: char *strncpy(char *dest, const char *src, size_t count) { char *tmp = dest; while (count && *src) { *tmp++ = *src++; count--; } if (count) { size_t count2; while (count & (sizeof(long) - 1)) { *tmp++ = '\0'; count--; } count2 = count / sizeof(long); while (count2) { *((long *)tmp)++ = '\0'; count2--; } count &= (sizeof(long) - 1); while (count) { *tmp++ = '\0'; count--; } } return dest; } //Peter - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/