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MP3 16 kbps Bit Rate with Encryption

We tested the MP3 16 kbps bit rate with encryption, using the dest2 physical server and Vitual Machine (VM) environments, which compares with results of non-encryption from MP3 16 kbps Bit Rate without Encryption. The OS remained Windows 2008 R2 x64.

Physical Server on Single Hex Core

These tests were performed on Hardware Profile 1: a physical server on a single hex core of Dell R410. The three graphs below compare system CPU usage and audio quality-related metrics, max jitter and max delta.

Figure 57: Comparison of Physical Server System CPU Usage of MP3 16kbps encryption vs non-encryption
Figure 58: Comparison of Physical Server Max Jitter of MP3 16kbps encryption vs non-encryption
Figure 59: Comparison of Physical Server Max Delta of MP3 16kbps encryption vs non-encryption

In the graphs above, encryption consumes slightly higher system CPU than does non-encryption. Max Jitter and Max Delta consume much more CPU with encryption, than without. If a slightly higher delay due to latency introduced by encryption is acceptable, then recommended and preferred port capacity would be 210 ports—only a 12.5% reduction from the peak capacity of 240 ports offered by non-encryption. If the audio quality strictly applies, then the recommended port capacity can be as low as 120 ports. Peak port capacity could be the same 270 ports as non-encryption, if the delay is acceptable.

The table below lists system disk IOPS:

Figure 60: IOPS on physical server of single hex core, MP3 only, 16 Kbps, encryption

Ports Physical Server Disk IOPS
Total Reads Writes
60 14.66 0.036 14.62
120 24.00 0.041 23.95
180 33.42 0.029 33.39
210 37.65 0.030 37.62
240 42.21 0.029 42.18
270 47.18 0.036 47.14
300 51.44 0.011 51.43
330 55.81 0.006 55.81
360 60.99 0.002 60.99
390 67.12 0.003 67.11

The graph below compares system disk IOPS on a physical server IOPS with non-encryption:

Figure 61: Comparison of System Disk IOPS on Single Hex Core Physical Server, MP3 16kbps encryption vs non-encryption

System disk IOPS is nearly the same for encryption and non-encryption; both increase slightly at a higher port capacity. Some of that can be attributed by other disk IO operations, such as encryption key files.

The table below lists MCP IOPS:

Figure 62: MCP IOPS on physical server of single hex core, MP3 only, 16 Kbps, encryption

Ports Physical Server MCP IOPS
Total Reads Writes
60 16.53 8.88 7.65
120 32.59 17.69 14.91
150 40.40 21.96 18.44
180 48.46 26.46 22.01
210 56.35 30.83 25.52
240 64.32 35.24 29.08
270 72.28 39.64 32.64
300 80.06 43.95 36.11
330 88.61 48.53 40.07
360 100.48 52.91 47.57

The graph below compares total MCP IOPS between encryption and non-encryption:

Figure 63: MCP IOPS on Single Hex Core Physical Server, MP3 16Kbps encryption vs non-encryption

MCP IOPS for encryption increases when port capacity increases. As seen in Figure: Comparison of System Disk IOPS on Single Hex Core Physical Server, MP3 16kbps encryption vs non-encryption, increase for disk IOPS is much smaller for encryption, so here the increase should be attributed to network IOs.

VMs on Dual Hex Cores Server

The testing for MP3 16kbps with encryption was conducted on the VM Profile 4 based on Hardware Profile 4 of a dual hex cores server, same as non-encryption in the 16knps tests VMs on Dual Hex Cores Server. Six VMs were configured while only one MCP was installed on each Windows VM. Below are three graphs comparing overall CPU usage, audio quality related max jitter and max delta for MP3 16kbps encryption vs non-encryption:

Figure 64: Comparison of Overall VMs CPU Usage of MP3 16kbps encryption vs non-encryption
Figure 65: Comparison of Overall VMs Max Jitter of MP3 16kbps encryption vs non-encryption
Figure 66: Comparison of Overall VMs Max Delta of MP3 16kbps encryption vs non-encryption

The VM environment exhibits a similar trend: slightly overall CPU usage for the encryption profile, and much higher for max jitter and max delta. Applying the same criteria from the physical server results, if a slightly higher delay (due to latency introduced by encryption) is acceptable, then the recommended and preferred port capacity could be 600 ports—only a 16.7% reduction of the peak 720 ports with non-encryption. If audio quality strictly applies, the recommended ports can be as low as 480 ports. And if some delay is acceptable, then the peak port capacity can be the same 840 ports as non-encryption.

The overall system disk IOPS for all 6 VMs is listed below:

Figure 67: Overall Disk IOPS on all 6 VMs of dual hex cores, MP3 only, 16 Kbps, encryption

Ports Overall 6 VMs Disk IOPS SSD Drive Disk IOPS
Total Reads Writes Total Reads Writes
120 28.70 0.004 28.69 21.881 0.000 21.881
360 67.46 0.004 67.46 56.238 0.000 56.238
480 87.56 0.026 87.54 74.903 0.000 74.903
600 108.01 0.015 107.99 93.647 0.000 93.647
660 119.49 0.005 119.48 104.304 0.000 104.304
720 128.76 0.020 128.74 114.441 0.000 114.441
780 137.68 0.015 137.66 123.210 0.002 123.209
840 146.99 0.009 146.98 132.646 0.002 132.644
900 154.68 0.025 154.66 140.145 0.002 140.143

The graph below compares system disk IOPS with encryption and with non-encryption, on the same VM environment:

Figure 68: Comparison of Overall 6 VMs Disk IOPS MP3 16 kbps encryption vs non-encryption

As with the physical server tests, encryption increases as port capacity increases. Also as with the physical server tests, some of that can be attributed to extra disk IO operations.

The table below lists Data throughputs for encryption:

Figure 69: Data Throughputs for MP3 only, 16 kbps, encryption

Ports Overall Disk KB/sec SSD Drive Disk KB/sec
Total Reads Writes Total Reads Writes
120 387.99 0.02 387.97 304.229 0.000 304.229
360 1096.82 22.54 1074.28 876.599 0.000 876.599
480 1344.60 107.95 1236.65 1191.403 0.006 1191.397
600 2187.50 348.40 1839.09 1532.171 0.000 1532.171
660 2024.16 35.09 1989.07 1652.232 0.000 1652.232
720 1955.33 99.81 1855.51 1803.207 0.006 1803.201
780 2572.79 205.15 2367.64 1982.733 0.024 1982.709
840 2534.97 28.65 2506.32 2097.871 0.043 2097.829
900 2851.85 119.47 2732.38 2297.264 0.007 2297.257

Using Formula 1...

MP3 bitrate * Ports / 8 = KB/sec
Or 16kbps * Ports / 8 =KB/sec if MP3 is 16kbps

...take two samples (120 & 720) from the above table above, and apply them to Formula 1:

16 kpbs * 120 / 8 = 240 kb close to 304 in the table (in SSD)
16 kpbs * 720 / 8 = 14400 kb close to 1803 in the table (in SSD)

The measurements from real testing for MP3 16kbps encryption are slightly higher than these calculations predict, due to other file, such as metadata and JSON files, being saved on the same cache folder.

The graph below compares overall data throughputs with no encryption:

Figure 70: Comparison of Overall 6 VMs Data Throughputs MP3 16 kbps encryption vs non-encryption

The data throughputs for encryption increase slightly when port capacity increases, matching a similar trend with system disk IOPS.

The table below lists overall MCP IOPS from all 6 VMs:

Figure 71: Overall MCP IOPS from 6 VMs of dual hex core, MP3 only, 16kbps, encryption

Ports Overall 6 VMs MCP IOPS
Total Reads Writes
120 34.874 17.638 17.236
360 102.624 52.900 49.724
480 130.285 70.377 59.909
600 168.849 87.766 81.083
660 186.175 96.882 89.293
720 193.248 105.171 88.077
780 219.395 114.398 104.997
840 235.730 123.009 112.720
900 252.198 131.682 120.516

The graph below compares performance of the same configuration, except with non-encryption:

Figure 72: MCP IOPS from 6 VMs of dual hex core, MP3 only, 16kbps, encryption vs non-encryption

MCP IOPS performance is affected slightly by encryption, similar to the trend expressed in the physical server results.

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This page was last modified on 25 September 2017, at 05:29.