"John Olbert" <someone@snet.net> wrote in message
news:7CEA5B7D-B6C9-4149-9B2E-52B25C15397E@microsoft.com...
>I am still pursuing why the DataSet.ReadXml() is so slow on the WinCe
>device
> (a Sh4 running at 400mhz). I remembered that Netcf App's will run on the
> Desktop so using Environment.TickCount I did a simple benchmarking of
> ReadXml, displaying the milliseconds in a MessageBox. I ran the code
> standalone (not under the debugger) in both the WinCe device and the
> Desktop.
> The WinCe runs at about 400mhz and the Desktop at about 1.8ghz (4.5 times
> faster). I found that the load time on the Desktop was about 337 times
> faster
> then on the WinCe device. I did not expect this. I assumed that the
> slowness
> of the Netcf ReadXml() was a combination of the processor speed and the
> "simplified" nature of the Netcf code. Apparently not. It appears that the
> "slowness" lies mainly with aspects of the WinCe device other then raw
> processor speed and not much with the difference between Net and Netcf
> code.
>
> Is this correct?
>
> Thanks.
>
> --John Olbert
> javo2000@snet.net
>
> --
> John Olbert
>

"Ilya Tumanov [MS]" <ilyatum@online.microsoft.com> wrote in message
news:43e008c8$1@news.microsoft.com...
> 1. Desktop runs at 1.8 GHz, device at 0.4 GHz. (x4.5)
>
> 2. Desktop can execute 3-4 commands per cycle; device can execute one or
> less (x3-5)
>
> 3. Desktop has 64 (128 for dual channel) bit DDR/DDR2 memory; device
> probably has 16 or 32 bit SDR @100MHz. (x50 on memory moves).
>
> 4. Desktop is CISC, device is RISC, CISC commands are shorter on average
> due to variable length and each does more. That hits device hard because
> of tiny cache and very slow memory. (x2)
>
> 5. Desktop uses highly optimized JIT; device uses fast compact JIT which
> produces especially slow code on NETCF V1 non-ARM CPUs. (x10)
>
>
>
> Let's see: 4.5x4x2x10 = 360. Sounds about right.
>
>
>
> By the way, code for ReadXml() was optimized in NETCF V1 SP2 (current
> version is SP3), it's about twice as fast as in RTM.
>
> JIT was optimized and unified for all CPUs in NETCF V2 and is about twice
> as fast for ARM (which was already fastest in V1).
>
> You might get x5 gain for SH4 with NETCF V2 or even more.
>
>
>
> Now, you also could optimize ReadXml():
>
>
>
> 1. Make sure schema is preloaded into data set, no schema means inference
> and that is very slow.
>
> 2. Map columns to attributes and use related tables, not nested. I've
> posted utility to make this change for existing XML/Schema, please use
> search below if you interested.
>
> 3. Avoid DateTime columns as they are very slow to parse. If you need
> DateTime, consider passing ticks instead.
>
>
>
> Keep in mind it would never be as fast as desktop, but you should be able
> to make speed acceptable.
>
>
> --
> Best regards,
>
>
> Ilya
>
> This posting is provided "AS IS" with no warranties, and confers no
> rights.
>
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>
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> "John Olbert" <someone@snet.net> wrote in message
> news:7CEA5B7D-B6C9-4149-9B2E-52B25C15397E@microsoft.com...
>>I am still pursuing why the DataSet.ReadXml() is so slow on the WinCe
>>device
>> (a Sh4 running at 400mhz). I remembered that Netcf App's will run on the
>> Desktop so using Environment.TickCount I did a simple benchmarking of
>> ReadXml, displaying the milliseconds in a MessageBox. I ran the code
>> standalone (not under the debugger) in both the WinCe device and the
>> Desktop.
>> The WinCe runs at about 400mhz and the Desktop at about 1.8ghz (4.5 times
>> faster). I found that the load time on the Desktop was about 337 times
>> faster
>> then on the WinCe device. I did not expect this. I assumed that the
>> slowness
>> of the Netcf ReadXml() was a combination of the processor speed and the
>> "simplified" nature of the Netcf code. Apparently not. It appears that
>> the
>> "slowness" lies mainly with aspects of the WinCe device other then raw
>> processor speed and not much with the difference between Net and Netcf
>> code.
>>
>> Is this correct?
>>
>> Thanks.
>>
>> --John Olbert
>> javo2000@snet.net
>>
>> --
>> John Olbert
>>
>
>