<div dir="ltr"><div dir="ltr"><div dir="ltr">Hi Bill,<div><br></div><div> FYI, our software radar at MIT Haystack (Ettus USRP N210 hardware as the source; GbE interface, running 25 complex megasamples / second at 16 bit depth) goes to a recorder agent that formats to Digital RF. This streams about 191 MB/sec of HDF5 files produced by the Digital RF API to a ring buffer inside a ramdisk, so going directly to memory. A subsequent agent processes power spectra with heavy reduction to a conventional spinning disk set (RAID 6, I believe) with a GlusterFS** cloud overlaid. This all uses workstation/general purpose computing on Ubuntu platforms. Note that we directly run a cable between the USRP and the computer and do not have it pass through any switches/routers. </div><div><br></div><div> So I guess I don't have a data point because our RAM disk buffers any slowdowns until we get it to spinning media. We use a ~100 GB ram buffer which provides probably 230 seconds of realtime soak per channel (x 2 channels for us). I know that we tried writing the 191 MB/second to spinning disks and it does not work - one needs SSDs at that rate. Probably worth trying SSDs in your testing.</div><div> </div><div> Aside: we do find that writing continuously to spinning media makes it die faster than normal since the manufacturers do not guarantee performance with continual write unless you buy Enterprise/server grade hardware - 10x more expensive, naturally. This is in line with Google's server farm experience using JBOD or equivalent systems.</div><div><br></div><div>73</div><div>Phil W1PJE</div><div><br></div><div>** "GlusterFS is a scalable network filesystem suitable for data-intensive tasks such as cloud storage and media streaming." <a href="https://www.gluster.org">https://www.gluster.org</a></div></div></div></div><br><div class="gmail_quote"><div dir="ltr" class="gmail_attr">On Wed, May 29, 2019 at 10:08 AM Engelke, Bill via TangerineSDR <<a href="mailto:tangerinesdr@lists.tapr.org">tangerinesdr@lists.tapr.org</a>> wrote:<br></div><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left-width:1px;border-left-style:solid;border-left-color:rgb(204,204,204);padding-left:1ex">
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<p class="MsoNormal"><span style="font-size:12pt;font-family:"Times New Roman",serif">Benchmarking Digital_rf on Odroid<u></u><u></u></span></p>
<p class="MsoNormal"><span style="font-size:12pt;font-family:"Times New Roman",serif"><u></u> <u></u></span></p>
<p class="MsoNormal"><span style="font-size:12pt;font-family:"Times New Roman",serif">There have been some deep concerns about the ability of a SBC to keep up with saving spectrum data using HDF5 (here using the MIT Digital_rf package, which uses HDF5 internally).
I installed Digital_rf on my Odroid XU4 and ran the benchmarks that are included in the Examples folder.<u></u><u></u></span></p>
<p class="MsoNormal"><span style="font-size:12pt;font-family:"Times New Roman",serif"><u></u> <u></u></span></p>
<p class="MsoNormal"><span style="font-size:12pt;font-family:"Times New Roman",serif">Writing to MicroSd card in the XU4 (SanDisk Ultra Plus, claimed speed 80 MB/sec), benchmark-reported speeds<u></u><u></u></span></p>
<p class="MsoNormal" style="margin-left:33pt;text-indent:0in">
<u></u><span style="font-family:"Times New Roman",serif"><span>1.<span style="font-style:normal;font-variant-caps:normal;font-weight:normal;font-stretch:normal;font-size:7pt;line-height:normal;font-family:"Times New Roman"">
</span></span></span><u></u><span style="color:rgb(31,73,125)">Writing raw binary data directly 133.36 MB/sec</span><span style="font-family:"Times New Roman",serif"><u></u><u></u></span></p>
<p class="MsoNormal" style="margin-left:33pt;text-indent:0in">
<u></u><span style="font-family:"Times New Roman",serif"><span>2.<span style="font-style:normal;font-variant-caps:normal;font-weight:normal;font-stretch:normal;font-size:7pt;line-height:normal;font-family:"Times New Roman"">
</span></span></span><u></u><span style="color:rgb(31,73,125)">Writing “simple single write” in HDF5 154.14 MB/sec </span><span style="font-family:"Times New Roman",serif"><u></u><u></u></span></p>
<p class="MsoNormal" style="margin-left:33pt;text-indent:0in">
<u></u><span style="font-family:"Times New Roman",serif"><span>3.<span style="font-style:normal;font-variant-caps:normal;font-weight:normal;font-stretch:normal;font-size:7pt;line-height:normal;font-family:"Times New Roman"">
</span></span></span><u></u><span style="color:rgb(31,73,125)">Writing “simple single write” in HDF5 with checksum 71.29 MB/sec</span><span style="font-family:"Times New Roman",serif"><u></u><u></u></span></p>
<p class="MsoNormal" style="margin-left:33pt;text-indent:0in">
<u></u><span style="font-family:"Times New Roman",serif"><span>4.<span style="font-style:normal;font-variant-caps:normal;font-weight:normal;font-stretch:normal;font-size:7pt;line-height:normal;font-family:"Times New Roman"">
</span></span></span><u></u><span style="color:rgb(31,73,125)">Writing “ “ “ with checksum + compression L1 8.01 MB/sec </span><span style="font-family:"Times New Roman",serif"><u></u><u></u></span></p>
<p class="MsoNormal"><span style="color:rgb(31,73,125)">Unexpected results here:</span><span style="font-size:12pt;font-family:"Times New Roman",serif"><u></u><u></u></span></p>
<p class="MsoNormal"><span style="color:rgb(31,73,125)">a. HDF5 "simple write" is faster than writing raw binary</span><span style="font-size:12pt;font-family:"Times New Roman",serif"><u></u><u></u></span></p>
<p class="MsoNormal"><span style="color:rgb(31,73,125)">b. top two speeds are faster than the claimed speed of the MicroSD card. Maybe the benchmark is measuring a burst rate during just the HDF5 processing (?) Maybe there is some caching or buffering going on.</span><span style="font-size:12pt;font-family:"Times New Roman",serif"><u></u><u></u></span></p>
<p class="MsoNormal"><span style="font-size:12pt;font-family:"Times New Roman",serif"><u></u> <u></u></span></p>
<p class="MsoNormal"><span style="color:rgb(31,73,125)">Writing to Western Digital USB 3 (spinning) external 4TB hard drive (incl. 64 MB internal cache) – benchmark-reported speeds</span><span style="font-size:12pt;font-family:"Times New Roman",serif"><u></u><u></u></span></p>
<p class="MsoNormal" style="margin-left:33pt;text-indent:0in">
<u></u><span style="font-family:"Times New Roman",serif"><span>1.<span style="font-style:normal;font-variant-caps:normal;font-weight:normal;font-stretch:normal;font-size:7pt;line-height:normal;font-family:"Times New Roman"">
</span></span></span><u></u><span style="color:rgb(31,73,125)">Writing raw binary data directly 103.66 MB/sec</span><span style="font-family:"Times New Roman",serif"><u></u><u></u></span></p>
<p class="MsoNormal" style="margin-left:33pt;text-indent:0in">
<u></u><span style="font-family:"Times New Roman",serif"><span>2.<span style="font-style:normal;font-variant-caps:normal;font-weight:normal;font-stretch:normal;font-size:7pt;line-height:normal;font-family:"Times New Roman"">
</span></span></span><u></u><span style="color:rgb(31,73,125)">Writing “simple single write” in HDF5 96.04 MB/sec </span><span style="font-family:"Times New Roman",serif"><u></u><u></u></span></p>
<p class="MsoNormal" style="margin-left:33pt;text-indent:0in">
<u></u><span style="font-family:"Times New Roman",serif"><span>3.<span style="font-style:normal;font-variant-caps:normal;font-weight:normal;font-stretch:normal;font-size:7pt;line-height:normal;font-family:"Times New Roman"">
</span></span></span><u></u><span style="color:rgb(31,73,125)">Writing “simple single write” in HDF5 with checksum 55.02 MB/sec</span><span style="font-family:"Times New Roman",serif"><u></u><u></u></span></p>
<p class="MsoNormal" style="margin-left:33pt;text-indent:0in">
<u></u><span style="font-family:"Times New Roman",serif"><span>4.<span style="font-style:normal;font-variant-caps:normal;font-weight:normal;font-stretch:normal;font-size:7pt;line-height:normal;font-family:"Times New Roman"">
</span></span></span><u></u><span style="color:rgb(31,73,125)">Writing “ “ “ with checksum + compression L1 7.67 MB/sec </span><span style="font-family:"Times New Roman",serif"><u></u><u></u></span></p>
<p class="MsoNormal"><span style="color:rgb(31,73,125)">These results make a bit more sense than the MicroSD result. I can't find a claimed transfer speed for this hard drive on Western Digital's site.<u></u><u></u></span></p>
<p class="MsoNormal"><span style="color:rgb(31,73,125)"><u></u> <u></u></span></p>
<p class="MsoNormal"><span style="color:rgb(31,73,125)">IF these results are representative (a big “if”) – then even a 4 TB spinning hard drive will be able to keep up with the PSWS data write rate. If anyone can confirm, reproduce, add to, or refute these results,
I am most interested to know…</span><span style="font-size:12pt;font-family:"Times New Roman",serif"><u></u><u></u></span></p>
<p class="MsoNormal"><u></u> <u></u></p>
<p class="MsoNormal">-73-<u></u><u></u></p>
<p class="MsoNormal">W. D. Engelke (Bill), Asst. Research Engr. AB4EJ<u></u><u></u></p>
<p class="MsoNormal">Center for Advanced Public Safety<u></u><u></u></p>
<p class="MsoNormal">Cyber Hall<u></u><u></u></p>
<p class="MsoNormal">The University of Alabama<u></u><u></u></p>
<p class="MsoNormal">Tuscaloosa, AL 35487<u></u><u></u></p>
<p class="MsoNormal">Desk: (205) 348-7244<u></u><u></u></p>
<p class="MsoNormal">Mobile: (205) 764-3099<u></u><u></u></p>
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</blockquote></div><br clear="all"><div><br></div>-- <br><div dir="ltr" class="gmail_signature">----<br>Phil Erickson<br><a href="mailto:phil.erickson@gmail.com" target="_blank">phil.erickson@gmail.com</a><br></div>