From: Paul Crawford <psc@sat.dundee.ac.uk>
To: dosemu <linux-msdos@vger.kernel.org>
Cc: Bart Oldeman <bartoldeman@gmail.com>
Subject: Re: Warning about kernel 4.2 performance (revised)
Date: Wed, 14 Oct 2015 20:10:20 +0100 [thread overview]
Message-ID: <561EA89C.6040203@sat.dundee.ac.uk> (raw)
In-Reply-To: <CABHtM7UDCoknfXqNczSgfqRhQchaqnfW1udLgGM8+NuBi2j=gA@mail.gmail.com>
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 just
> 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 can
> be worked around though with some more coding.
In our case the ability to get hardware interrupts routed through to the
DOS emulator's code in a prompt manner is VERY important. In fact that
is one major reason we have generally not played with the 64-bit version
very much in the past.
By "prompt" I mean less than 10us or so which was no trouble in the
native 286/DOS era, and today should not be a problem given a typical
CPU can execute some 30k instructions in that time, but we know that is
not how software bloat and indirection go :(
Regards,
Paul
next prev parent reply other threads:[~2015-10-14 19:10 UTC|newest]
Thread overview: 20+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-10-03 7:56 Warning about kernel 4.2 performance Andrew Bird
2015-10-04 4:27 ` solarflow99
2015-10-04 7:16 ` Andrew Bird
2015-10-04 8:35 ` Felix Miata
2015-10-04 9:27 ` Andrew Bird
2015-10-04 10:32 ` Warning about kernel 4.2 performance (revised) Andrew Bird
2015-10-04 17:26 ` Felix Miata
2015-10-04 17:36 ` Stas Sergeev
2015-10-05 9:47 ` Andrew Bird
2015-10-05 11:20 ` Stas Sergeev
2015-10-05 12:03 ` Andrew Bird
[not found] ` <CABHtM7Wn44rMU11iKx8H2Z3gZMwWzLKfD7b+KZP8m+1RRmxQ3A@mail.gmail.com>
2015-10-14 18:46 ` Fwd: " Bart Oldeman
2015-10-14 19:10 ` Paul Crawford [this message]
2015-10-14 22:08 ` Stas Sergeev
2015-10-16 2:07 ` solarflow99
2015-10-16 20:20 ` Stas Sergeev
2015-10-04 16:55 ` Warning about kernel 4.2 performance Stas Sergeev
2015-10-04 20:45 ` solarflow99
2015-10-05 9:33 ` Andrew Bird
2015-10-05 10:05 ` Stas Sergeev
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