Gary Rubin Posted March 16, 2007 Report Share Posted March 16, 2007 If I remember correctly, there was supposed to be a speed enhancement in some of the math functions between LV7.1.1 and LV8.x. I don't currently have access to LV8.x. Could someone please run the attached VI in both 7.1 and 8.x and let me know the speed results? Thanks, Gary Quote Link to comment
French LVer Posted March 16, 2007 Report Share Posted March 16, 2007 Tested on an Intel Pentium M 1.7 GHz 512 Mo. For 10 FFT => LV 7.1 : 126.5 to 128.2 ms => LV 8.2 : 143.6 to 145.0 ms Might be better on a real computer Quote Link to comment
Gary Rubin Posted March 16, 2007 Author Report Share Posted March 16, 2007 QUOTE(French LVer @ Mar 15 2007, 11:11 AM) Tested on an Intel Pentium M 1.7 GHz 512 Mo.For 10 FFT => LV 7.1 : 126.5 to 128.2 ms => LV 8.2 : 143.6 to 145.0 ms Might be better on a real computer Thank you very much! I have to say that you have managed to raise more questions than answers... My results are: LV7.1.1 2.4GHz P4 , 2GB RAM, lots of other crap open: 249 ms. EDIT: WinXP Pro SP2. LV7.1.1 2.4GHz Dual Xeon, 1GB RAM: 274 ms. EDIT: Win2k SP3. Questions: Why is yours twice as fast as mine? Why is your LV7.1 faster than LV8.2? Why is my P4 with lots of stuff in the background faster than my Xeon? Anyone have any thoughts? Quote Link to comment
AnalogKid2DigitalMan Posted March 16, 2007 Report Share Posted March 16, 2007 LV 8.2 1st run 166, 2nd run 106, 3rd through 5th runs 96-97. LV freshly opened with your code Running P4 Duo Core 2.8GHz, 1G RAM (500M free), Win XP Pro SP2. It was odd that the first run was so slow, 2nd run was faster, subsequent runs faitly repeatable. Maybe an initial memory allocation? Sorry, only 8.2 available to me. Quote Link to comment
Eugen Graf Posted March 16, 2007 Report Share Posted March 16, 2007 LV 8.0.1 AMD Athlon 64 3200+ 2.01 GHz 1 GB RAM XP+SP2 at 10 repeats have durations from 127 to 130 ms Eugen Quote Link to comment
Gary Rubin Posted March 16, 2007 Author Report Share Posted March 16, 2007 Thanks to those who ran this for me. I guess I haven't yet confirmed whether LV8.x FFT is faster than the LV7.1.1 version, but I did notice something interesting. I've attached a new vi that runs the one I posted above and plots runtime as function of FFT length. On my system, runtime starts to increase more-or-less linearly after 128kpoints. I'm guessing, therefore, that below 128kpoints most of the time is spent doing the FFT, and I can see the logN part of the execution time. Above 128kpoints FFT, Labview is spending more time doing memory allocation than actually performing the calculations, so I'm mostly seeing a linear increase in time it takes to do the buffer allocation. All you guys with the faster times than me probably have faster memory, or at least a faster memory bus. Does that sound reasonable? Gary Quote Link to comment
AnalogKid2DigitalMan Posted March 16, 2007 Report Share Posted March 16, 2007 Gary: I ran your original vi on my older Dell Precision 370 2.8GHz single core (circa 8-2004), 512M RAM (185M free) LV8.2 Win XP SP2. 81-82msec consistently (FASTER) The original test I ran was on a Precision 380 circa 5-2005 I do not know RAM specifics, but using AIDA32 I did memory Read/Write tests. Pecision 370: Read 5274MB/sec, Write 2081MB/sec Precision 380: Read 5578MB/sec, Write 2152 MB/sec. Do not know why the slower 370 memory executes faster. Quote Link to comment
Gary Rubin Posted March 16, 2007 Author Report Share Posted March 16, 2007 QUOTE(AnalogKid2DigitalMan @ Mar 15 2007, 02:28 PM) Do not know why the slower 370 memory executes faster. Thanks. Quite the headscratcher... Your signature seems quite fitting at the moment. Gary Quote Link to comment
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.