From mboxrd@z Thu Jan 1 00:00:00 1970 From: Stas Sergeev Subject: Re: Warning about kernel 4.2 performance (revised) Date: Thu, 15 Oct 2015 01:08:01 +0300 Message-ID: <561ED241.6030307@list.ru> References: <20151003085631.02f5b16dfebc7020bf3a1edb@spheresystems.co.uk> <20151004081607.881df23245f969d66eba63b0@spheresystems.co.uk> <5610E4E5.2090802@earthlink.net> <20151004113203.b07e3f6ac66bcba747d75903@spheresystems.co.uk> <56116148.9050608@earthlink.net> <561163AA.6040706@list.ru> <20151005104705.7b2df50cac63a976412ecc22@spheresystems.co.uk> <56125D09.4000108@list.ru> <20151005130317.8c0c970a8953b6792305b5d1@spheresystems.co.uk> <561EA89C.6040203@sat.dundee.ac.uk> Mime-Version: 1.0 Content-Transfer-Encoding: QUOTED-PRINTABLE Return-path: DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=list.ru; s=mail; h=Content-Transfer-Encoding:Content-Type:In-Reply-To:MIME-Version:Date:Message-ID:From:Cc:References:To:Subject; bh=+0zN+NGc5qLmlWK7B2xdXmyrUXHAbSzrVN5EWlGHZac=; b=j2HlQNduLhVS/O0d7WKyYd+26iTv/A/RViRzmrxoxnIogjIigfaUZY4iWlU6MsY9kqVDMOzPix/VPNST29kNyis1rqMwf0DEE1pK0tTHAj5YIf5WMjMKSZFdvJ9jAKZQtT/lTwyhtjuvohqxuZN8980J5dtHk/2RVALL/TtscFA=; In-Reply-To: <561EA89C.6040203@sat.dundee.ac.uk> Sender: linux-msdos-owner@vger.kernel.org List-ID: Content-Type: text/plain; charset="utf-8"; format="flowed" To: Paul Crawford , dosemu Cc: Bart Oldeman 14.10.2015 22:10, Paul Crawford =D0=BF=D0=B8=D1=88=D0=B5=D1=82: > Hi Bart, >> At least on Westmere+ CPUs (first gen Core i3/i5/i7) KVM can run >> "unrestricted guest" mode which behaves like real mode and seems jus= t >> as fast as vm86() but it traps less than vm86 so some things that >> dosemu depends upon (e.g. that INTs are trapped) do not work. That c= an >> be worked around though with some more coding. > > In our case the ability to get hardware interrupts routed through to=20 > the DOS emulator's code in a prompt manner is VERY important. If you mean the hardware interrupts from real hardware (rather than from the emulated hw), then the only way to keep this alive is to write an UIO backend: https://www.kernel.org/doc/htmldocs/uio-howto/about.html#how_uio_works And that should be written by someone who at least has the test case, which means you. :) -- To unsubscribe from this list: send the line "unsubscribe linux-msdos" = in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html