Date: Sat, 08 Dec 2012 19:52:34 -0800 From: "Ronald F. Guilmette" <rfg@tristatelogic.com> Cc: freebsd-hackers@freebsd.org Subject: Re: FreeBSD for serious performance? (was: Re: 9.x -- New Install -- serious partition misalignment) Message-ID: <1830.1355025154@tristatelogic.com> In-Reply-To: <20121209014547.238070@gmx.com>
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In message <20121209014547.238070@gmx.com>,
"Dieter BSD" <dieterbsd@engineer.com> wrote:
>But don't brag about high-end hardware. But FreeBSD has dropped support
>for even semi-high-end hardware (DEC Alpha). So I'm stuck running it on
>AMD64. Nothing against AMD, they did what they could to try and make a silk
>purse (amd64) out of a sow's ear (x86). But even getting what passes for
>a high quality board in amd64/x86 land with good reviews doesn't compare.
>The firmware is absolute crap, and it's not like it is something you can
>ignore. BTW, real high end hardware is redundant, better than mil-spec,
>and provides better than 5-9s uptime. Been there, done that.
>
>Several chips/features aren't supported properly. PRs sit for years on end.
>
>> Performance has been degraded by a whopping 75% !
>
>Having a 4KiB misalignment is nothing compared with not having NCQ
>support. (Which even linux has, btw.) 25% performance would be a massive
>upgrade. Or even worse, having the disk driver go into an infinite loop
>with interrupts blocked, so *nothing* happens and all your incoming data
>is lost until you manually intervene.
>
>Speaking of alignment, I still get "partition 1 does not end on a
>track boundary" messages. FreeBSD has no clue where the track boundaries
>are and neither do I. Disks have used varying numbers of sectors/track
>for longer than FreeBSD has existed.
>
>This is your idea of serious?
In general, I agree with the point(s) you are making, but I do have a few
minor quibbles...
1) According to:
http://en.wikipedia.org/wiki/DEC_Alpha#Model_history
the last Alpha to be produced was shipped way back in 2004... eight years
ago... with a top speed of 1.3 GHz. I now have a cheap little media player
thingy sitting on my desk, and _each_ of its two cores runs faster than that.
In short, Alphas hardly constitute high-end hardware in this day and age.
2) Although I don't know a lot about boards, it is my understanding that
ASUS makes pretty good ones, and they have always worked for me (and the
firmware is typically quite good).
As regards to the Native Command Queuing.... all I can say is "Crap!"
I wasn't aware...until now... that FreeBSD did not support that. That
really is a rather entirely serious issue. But I do think that the
performance hit from that would be dwarfed by the performance hit that
could be caused by the AF misaligment problem.
And finally, yes, _nobody_ (except maybe the manufacturers) has known where
the actual physical track boundaries have been for a long long time now.
Regards,
rfg
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