From owner-freebsd-current Wed Mar 21 15:16: 9 2001 Delivered-To: freebsd-current@freebsd.org Received: from salmon.maths.tcd.ie (salmon.maths.tcd.ie [134.226.81.11]) by hub.freebsd.org (Postfix) with SMTP id 41FF237B71B; Wed, 21 Mar 2001 15:16:04 -0800 (PST) (envelope-from dwmalone@maths.tcd.ie) Received: from walton.maths.tcd.ie by salmon.maths.tcd.ie with SMTP id ; 21 Mar 2001 23:16:03 +0000 (GMT) Date: Wed, 21 Mar 2001 23:16:01 +0000 From: David Malone To: Bruce Evans Cc: Dag-Erling Smorgrav , current@FreeBSD.ORG, jhb@FreeBSD.ORG, jake@FreeBSD.ORG, Ian Dowse Subject: Re: Interesting backtrace... Message-ID: <20010321231601.A73422@walton.maths.tcd.ie> References: Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline User-Agent: Mutt/1.2.5i In-Reply-To: ; from bde@zeta.org.au on Mon, Mar 19, 2001 at 02:47:34PM +1100 Sender: owner-freebsd-current@FreeBSD.ORG Precedence: bulk X-Loop: FreeBSD.ORG On Mon, Mar 19, 2001 at 02:47:34PM +1100, Bruce Evans wrote: > > npx.c already has one "fix" for the overflow problem. The problem > > is may be that clocks don't work early any more. > > It must be that microtime() doesn't work early any more. I did a quick check, and it does seem that i586_bzero can be faster on the k6-2. I found it was about twice as fast for large buffers. This was timed in userland using the TSC. With a slightly simplified version of i586_bzero (I removed all the kernel specific stuff and had it always save the floating point state on the stack). A graph is at: http://www.maths.tcd.ie/~dwmalone/comp/bzero-band.ps The graph seems to peak at about 160kB/s, which seems plausable. The code is at: http://www.maths.tcd.ie/~dwmalone/comp/-time.S http://www.maths.tcd.ie/~dwmalone/comp/-time.c (It's crude, but seemed to produce moderately OK results. You get ocasional dips in the bandwidth due to using the tcs for timing. I only tried sizes which were a power of two, aswell...) David. To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-current" in the body of the message