From owner-freebsd-hackers Wed Feb 28 5: 7:57 2001 Delivered-To: freebsd-hackers@freebsd.org Received: from heechee.tobez.org (254.adsl0.ryv.worldonline.dk [213.237.10.254]) by hub.freebsd.org (Postfix) with ESMTP id 2BFBA37B718 for ; Wed, 28 Feb 2001 05:07:52 -0800 (PST) (envelope-from tobez@tobez.org) Received: by heechee.tobez.org (Postfix, from userid 1001) id A7EDE54F4; Wed, 28 Feb 2001 14:07:49 +0100 (CET) Date: Wed, 28 Feb 2001 14:07:49 +0100 From: Anton Berezin To: hackers@freebsd.org Subject: how to actually find out whether data hit the disk? Message-ID: <20010228140749.B29400@heechee.tobez.org> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline User-Agent: Mutt/1.2.5i Sender: owner-freebsd-hackers@FreeBSD.ORG Precedence: bulk X-Loop: FreeBSD.ORG Hi, I am doing the following, on the partition with softupdates turned on: 1. fd = open("a file", O_CREAT) 2. mmap(fd) 3. sequencial write to mmapped region 4. some other processing 5. munmap 6. unlink 7. close Since this is a supposedly high-perfomance application, I am interested that data do NOT hit the disk. I understand that softupdates do a good job at that. The time taken by step 4 is usually sub-second, but sometimes it can take longer (network delays etc.). The question is - is it possible to actually find out whether data hit the disk or not for a particular run of 1-7? &Anton. -- May the tuna salad be with you. To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-hackers" in the body of the message