From owner-freebsd-hackers Fri Apr 21 19:55:27 2000 Delivered-To: freebsd-hackers@freebsd.org Received: from celery.dragondata.com (celery.dragondata.com [205.253.12.6]) by hub.freebsd.org (Postfix) with ESMTP id 2692737B5FE for ; Fri, 21 Apr 2000 19:55:25 -0700 (PDT) (envelope-from toasty@celery.dragondata.com) Received: (from toasty@localhost) by celery.dragondata.com (8.9.3/8.9.3) id VAA29433 for hackers@freebsd.org; Fri, 21 Apr 2000 21:55:19 -0500 (CDT) (envelope-from toasty) From: Kevin Day Message-Id: <200004220255.VAA29433@celery.dragondata.com> Subject: Double buffered cp(1) To: hackers@freebsd.org Date: Fri, 21 Apr 2000 21:55:19 -0500 (CDT) X-Mailer: ELM [version 2.5 PL1] MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit Sender: owner-freebsd-hackers@FreeBSD.ORG Precedence: bulk X-Loop: FreeBSD.ORG Has anyone attempted to create a double buffered version of cp(1)? When copying from one disk to another, disk activity seems to ping-pong between the two, rather than keeping both active at the same time. If I were to fork and do something similar to afio, or maybe even doing something weird like using sendfile(it's faster than it sounds, and zero-copy), does anyone think I'd see any kind of speed boost? I'm effectively getting a little less than half the performance of just writing files filled with zero's, so I'm guessing this is where the bottleneck is, correct? -- Kevin To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-hackers" in the body of the message