From: Stefan Weil <sw@weilnetz.de>
To: Richard Henderson <rth@twiddle.net>, "Emilio G. Cota" <cota@braap.org>
Cc: qemu-trivial <qemu-trivial@nongnu.org>,
"Alex Bennée" <alex.bennee@linaro.org>,
qemu-devel@nongnu.org
Subject: Re: [Qemu-trivial] [Qemu-devel] [PATCH] tcg: optimise memory layout of TCGTemp
Date: Mon, 30 Mar 2015 07:43:45 +0200 [thread overview]
Message-ID: <5518E291.6020708@weilnetz.de> (raw)
In-Reply-To: <5518742e.451f460a.1d9b.66ce@mx.google.com>
Am 29.03.2015 um 23:52 schrieb Richard Henderson:
> No decrease in boot time is good. We /know/ we're saving memory, after all.
Well, I would not mind a decrease in boot time, too.
The more it decreases, the better. :-)
To be honest: in my version I only used 1 bit bitfield entries for
boolean values, but 8 bit values (aligned on byte boundaries)
for other values because as far as I know, most (all?) cpu
architectures will need more time to extract some bits from
a machine word than to extract a byte.
I have no idea whether this makes a difference in performance
as I did not run any runtime benchmark.
Stefan
WARNING: multiple messages have this Message-ID (diff)
From: Stefan Weil <sw@weilnetz.de>
To: Richard Henderson <rth@twiddle.net>, "Emilio G. Cota" <cota@braap.org>
Cc: qemu-trivial <qemu-trivial@nongnu.org>,
"Alex Bennée" <alex.bennee@linaro.org>,
qemu-devel@nongnu.org
Subject: Re: [Qemu-devel] [PATCH] tcg: optimise memory layout of TCGTemp
Date: Mon, 30 Mar 2015 07:43:45 +0200 [thread overview]
Message-ID: <5518E291.6020708@weilnetz.de> (raw)
In-Reply-To: <5518742e.451f460a.1d9b.66ce@mx.google.com>
Am 29.03.2015 um 23:52 schrieb Richard Henderson:
> No decrease in boot time is good. We /know/ we're saving memory, after all.
Well, I would not mind a decrease in boot time, too.
The more it decreases, the better. :-)
To be honest: in my version I only used 1 bit bitfield entries for
boolean values, but 8 bit values (aligned on byte boundaries)
for other values because as far as I know, most (all?) cpu
architectures will need more time to extract some bits from
a machine word than to extract a byte.
I have no idea whether this makes a difference in performance
as I did not run any runtime benchmark.
Stefan
next prev parent reply other threads:[~2015-03-30 5:43 UTC|newest]
Thread overview: 17+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-03-29 21:52 [Qemu-trivial] [Qemu-devel] [PATCH] tcg: optimise memory layout of TCGTemp Richard Henderson
2015-03-29 21:52 ` Richard Henderson
2015-03-30 5:33 ` [Qemu-trivial] " Stefan Weil
2015-03-30 5:33 ` Stefan Weil
2015-03-30 5:43 ` Stefan Weil [this message]
2015-03-30 5:43 ` Stefan Weil
2015-04-03 0:07 ` [Qemu-trivial] [PATCH v2] " Emilio G. Cota
2015-04-03 0:07 ` [Qemu-devel] " Emilio G. Cota
2015-04-03 8:13 ` [Qemu-trivial] " Stefan Weil
2015-04-03 8:13 ` [Qemu-devel] " Stefan Weil
2015-04-03 14:17 ` [Qemu-trivial] " Richard Henderson
2015-04-03 14:17 ` [Qemu-devel] " Richard Henderson
2015-04-07 14:59 ` [Qemu-trivial] " Alex Bennée
2015-04-07 14:59 ` [Qemu-devel] " Alex Bennée
-- strict thread matches above, loose matches on Subject: below --
2015-03-27 14:58 [Qemu-trivial] [PATCH] " Richard Henderson
2015-03-24 1:07 [Qemu-trivial] [Qemu-devel] [PATCH] tcg: pack TCGTemp to reduce size by 8 bytes Richard Henderson
2015-03-25 19:50 ` [Qemu-trivial] [PATCH] tcg: optimise memory layout of TCGTemp Emilio G. Cota
2015-03-27 9:55 ` [Qemu-trivial] [Qemu-devel] " Alex Bennée
2015-03-27 21:09 ` Emilio G. Cota
2015-03-30 9:55 ` Laurent Desnogues
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