Quoting Tiberiu Atudorei <tiberiu.atudorei@...>:

>
> Lies, damn lies...and benchmarks :)
>

Sorry for my repost, but I've just got an ideea for an interesting hack.
A way to blow up every decent benchmark result. And the best part is that
I think it is feasible. Indulge me for the next few lines.
I'm a Linux fan and I've always wondered what impact can have the 'double
buffering' upon performance: first we have an operating system disk cache,
and second a Firebird cache. Different algorithms, but the access speed is
pretty much the same. We are talking about common hardware, so we have
one CPU in the range of 1,5-3 GHz, and we are lucky if we have 2 CPU or
2 pseudo-CPU (HT). Just for the proof of concept, let's stick with an
Intel HT at 3 GHZ (AMD fans could consider an FX-51). Dual channel memory
interface, good DDR 400 RAM. Now the memory interface seems to be some
leverage factor. The bottleneck is obvious the interface to the hard-disk.
For servers I'm a SCSI fan, but the IDE is coming up with speed and (most
important) affordability. ATA133 or SATA 150 is no big difference , let's
presume that we are prepare for the future and we use all the tricks and
new gizmos: we use a SATA 150 with RAID 0 or RAID 10 (or RAID 01 ? another
subject for holly wars: RAID 10 vs. RAID 01).
So, let's see what we've got 'till now: the speed of a modern CPU is 1,5-3,
the memory varies form SDRAM 133 to DDRAM 400, the multiple CPU / HT doesn't
give us any real boost (just a 25% gain if we are lucky). What trick or gizmo
can give us a real boost?
A RAM disk, of course. There are such things, with PCI interfaces, bateries
included (if you get REAL lucky you get Durracell:) and memory as much as
you can afford it. Or maybe you can forget about hardware solutions and stick
with software solution, very cheap and effective. It's easier when you are in
Linux.
Now we came back to my dillema: how to balance the OS disk cache with the
FB page cache. Maybe the best answer is : you don't have to. What if we get
real lucky and we implement some sort of cache, a smaller but faster memory.
If you don't aim for much faster or much larger memory chances are that you
allready have it. Ladies and gentlemen, it's in your 200 USD video card,
featuring a 256 MB memory at 800-1000 MHz. Maybe an year ago I've read an
article on the IBM site how to implement a RAM disk using fast video memory.
Now is the challenge: considering we've got around 256 MB at 1000 MHz, how
would you tweak the system in order to make the swedish dolphin make an
application for a 'Flipper' remake? Any ideas?

Tiberiu Atudorei