From: Tom Kotwal on
Hi All,

I'm speccing out a new windows PC that I'll use with Xilinx tools,
probably Webpack and Modelsim, and I'm looking for some advice to make
sure the tools will run fast. I know memory is important, but what
else? Also, what pitfalls should I watch out for?

I'm not sure how relevant this info is, but I'm probably going to
target something in the ballpark of a Virtex-5 LX50. Also, I'm
planning on getting a laptop because I'll need to travel quite a bit
with it.

Some specific questions:

- Have people had any problems with Windows 7? 32 bit or 64? Is it
useful to have Win 7 Pro so that I can use XP mode?
- Core 2 Duo vs i7?
- How important is cache size?
- How much memory should I get? Is 4GB enough?

Thanks!

-Tom
From: whygee on
hi,

Tom Kotwal wrote:
> - Core 2 Duo vs i7?
depends if you can find a laptop with it.
It seems to be quite worth it but the i7 is much
more expensive... It may have changed since the
last time I've looked, Intel has just announced
i7 derivatives (i5 and i3 from memory, look /.)
for desktops and laptops.

> - How important is cache size?
very. So choose the laptop with the largest L2 & L3,
over raw speed : being memory access dependent,
many P&R algos will stall the CPU...
Also those algos are difficult to parallelize
so don't waste money on a quad-core,
one core will be busy with P&R while the other
will remain for the OS GUI.

Oh, I think that some Toshiba have 2 (two !)
disk drive slots. Might be interesting in RAID :-)

> - How much memory should I get? Is 4GB enough?
should be, add some swap too.
Check that your OS supports as much (well, the recent
kernels support at least 64GB but MS's marketing department has
crippled actual /use/ of detected RAM, see a past /. article).
But FAST memory and several channels are recommended.
Bandwidth and access time are to be preferred.

With small designs on Actel, I have seen that I don't
consume as much memory as I thought. Like 500M peak or so...
Vista consumes about as much :-D
Now I have not succeeded in running it under Linux
but I expect much more comfort.

....

I'm currently going the other route with a /small/ ACER ONE netbook
(Atom dual-thread CPU, XP and single DDR2 slot upgraded to 2GB)
so I can S&P&R in travel. I wonder what the results will be,
compared to the somewhat bulkier Toshiba with a Core2
at the same CPU speed. Price and size have been halved, however :-)

But given that most of the time is lost clicking the same dialogs
all the time, and that those damn antiviruses/toolbars/indexers/GUI widgets
waste RAM&cycles, I don't expect a big difference...
The much smaller size and the lower price make it more like
a commodity, something replaceable and that can be carried along...

> Thanks!
happy hacking,

> -Tom
yg

--
http://ygdes.com / http://yasep.org
From: General Schvantzkoph on
On Thu, 07 Jan 2010 09:24:27 -0800, Tom Kotwal wrote:

> Hi All,
>
> I'm speccing out a new windows PC that I'll use with Xilinx tools,
> probably Webpack and Modelsim, and I'm looking for some advice to make
> sure the tools will run fast. I know memory is important, but what else?
> Also, what pitfalls should I watch out for?
>
> I'm not sure how relevant this info is, but I'm probably going to target
> something in the ballpark of a Virtex-5 LX50. Also, I'm planning on
> getting a laptop because I'll need to travel quite a bit with it.
>
> Some specific questions:
>
> - Have people had any problems with Windows 7? 32 bit or 64? Is it
> useful to have Win 7 Pro so that I can use XP mode? - Core 2 Duo vs i7?
> - How important is cache size?
> - How much memory should I get? Is 4GB enough?
>
> Thanks!
>
> -Tom

For simulation cache size is very important. My benchmarking on Linux
shows that NC simulations run about 10% faster clock for clock on a Core2
with a 6M two level cache vs an iCore7 with a three level cache. The
difference between a 6M Core2 and a 4M Core2 is even greater. For Xilinx
place and routes the iCore7 is a little faster clock for clock.

One reason to get an iCore7 is that it can hold 12G of RAM at reasonable
prices. The large members of the V5 family need more than 8G, the LX300
uses 10G for example. If you are only using smaller FPGAs then 8G is
fine. I wouldn't consider anything less than 8G these days.

You also need a 64bit OS. If you must use Windows then get a 64 bit
version.

From: Gabor on
On Jan 7, 3:01 pm, General Schvantzkoph <schvantzk...(a)yahoo.com>
wrote:
> On Thu, 07 Jan 2010 09:24:27 -0800, Tom Kotwal wrote:
> > Hi All,
>
> > I'm speccing out a new windows PC that I'll use with Xilinx tools,
> > probably Webpack and Modelsim, and I'm looking for some advice to make
> > sure the tools will run fast. I know memory is important, but what else?
> > Also, what pitfalls should I watch out for?
>
> > I'm not sure how relevant this info is, but I'm probably going to target
> > something in the ballpark of a Virtex-5 LX50. Also, I'm planning on
> > getting a laptop because I'll need to travel quite a bit with it.
>
> > Some specific questions:
>
> > - Have people had any problems with Windows 7? 32 bit or 64? Is it
> > useful to have Win 7 Pro so that I can use XP mode? - Core 2 Duo vs i7?
> > - How important is cache size?
> > - How much memory should I get? Is 4GB enough?
>
> > Thanks!
>
> > -Tom
>
> For simulation cache size is very important. My benchmarking on Linux
> shows that NC simulations run about 10% faster clock for clock on a Core2
> with a 6M two level cache vs an iCore7 with a three level cache. The
> difference between a 6M Core2 and a 4M Core2 is even greater. For Xilinx
> place and routes the iCore7 is a little faster clock for clock.
>
> One reason to get an iCore7 is that it can hold 12G of RAM at reasonable
> prices. The large members of the V5 family need more than 8G, the LX300
> uses 10G for example. If you are only using smaller FPGAs then 8G is
> fine. I wouldn't consider anything less than 8G these days.
>
> You also need a 64bit OS. If you must use Windows then get a 64 bit
> version.

I'm running LX85T and LX110T designs pretty comfortably in 32-bit
Windows XP. Check with Xilinx before jumping into Windows 7, I don't
think the support is quite there yet. Also WinXP has been around
long enough to run the older versions you'll need to support the
legacy devices.

If you're not a GUI-driver, and want raw performance you're
probably best off with a 64-bit Linux rather than Windows. I've
seen many more bug reports on the Windows tool versions. It may
just be that more people use them, but I think the general
consensus is that the best performance comes using Linux. If
you need the notebook for typical office applications in
addition to the Xilinx stuff you may want to weigh that into
your OS choice, too.

Multiprocessor is nice for the ability to use the computer
while you're running synthesis, P&R, etc. Also the multicore
CPU's usually have faster front-side buses and larger cache,
which makes the tools run faster. Most of the processes
don't do enough disk access for the disk speed to be an
issue. Just be sure your memory is big enough to avoid
a lot of paging. 4GB will really be more like 3 GB if you're
running 32-bit windows.

regards,
gabor
From: emeb on
On Jan 7, 1:01 pm, General Schvantzkoph <schvantzk...(a)yahoo.com>
wrote:

> One reason to get an iCore7 is that it can hold 12G of RAM at reasonable
> prices. The large members of the V5 family need more than 8G, the LX300
> uses 10G for example. If you are only using smaller FPGAs then 8G is
> fine. I wouldn't consider anything less than 8G these days.
>
> You also need a 64bit OS. If you must use Windows then get a 64 bit
> version.

Interesting - what version of ISE are you basing this on? I'm using
10.1.3 to build against a V5 SX95T in only 4G on a Linux X86_64 system
and not running into any memory issues.

Eric