From mboxrd@z Thu Jan 1 00:00:00 1970 MIME-Version: 1.0 In-Reply-To: References: <10af1064d3ac35a8d2f62214d5eec485@gmx.de> Date: Fri, 15 Oct 2010 10:49:22 -0700 Message-ID: From: ron minnich To: Fans of the OS Plan 9 from Bell Labs <9fans@9fans.net> Content-Type: text/plain; charset=ISO-8859-1 Subject: Re: [9fans] =?iso-8859-7?q?=F0p?= Topicbox-Message-UUID: 66d221b2-ead6-11e9-9d60-3106f5b1d025 2010/10/15 Nemo : > So, when I hear migration, I just tend to see what happens after it has > been implemented and faces the spaghethy phase. And even if you get that right, it may not work well on hardware. We saw cases with linux migration, while migrating from one x86 to another, where valid FP values would cause the target to get an FP trap. Made no sense, but it's what happened, because the two x86's were different *implementations* of the same architecture. So, migration works well for all the really easy cases -- CPU you migrate to was fabbed by the same vendor in the same place with the same mask and microcode as the one you migrate from -- and can fail on anything tricky. That's why I don't like it either :-) ron