====== Latency Measurement Results ======

Read [[jack_latency_tests| background info]] about these tests.

===== Headline =====

Legend:

**HDA 1**: Intel ICH6\\             
**HDA 2**: ATI SB4x0\\
**HDA 3**: Intel 5 Series/3400 Series Chipset HDA (1458:a002)\\
**USB 1**: HY554\\
**USB 2**: Edirol UA-25 (Luis)\\
**USB 3**: Edirol UA-25 (Robin)\\

**64*2/48kHz**: jackd backend parameters ''-p64 -n2 -r48000''\\
**/S**: jackdmp synchronous mode\\
**RIL**: reported input latency\\
**ROL**: reported output latency\\


==== Table 1: Total round-trip Latency ====


Table 1 - Latency values for six different audio devices: three on-board HDA and three external USB.
^ ^ ^ ^HDA 1^^HDA 2^^HDA 3^^USB 1^^USB 2^^USB 3^^
^ ^RIL^ROL^frames^ms^frames^ms^frames^ms^frames^ms^frames^ms^frames^ms^^
|  64*2/48kHz/S |64|64|160.42|3.34|156.37|3.26|169.9|3.54|312.63|6.51|378.48|7.88|377.75|7.87|
|  64*2/48kHz   |64|128|224.42|4.68|220.38|4.59|233.88|4.87|376.63|7.85|442.48|9.22|441.75|9.2|
|  64*3/48kHz/S |64|128|223.42|4.65|220.38|4.59|232.85|4.85|376.63|7.85|442.47|9.22|441.75|9.2|
|  64*3/48kHz   |64|192|287.42|5.99|284.38|5.92|297.83|6.2|440.63|9.18|506.48|10.55|505.75|10.54|
| 128*2/48kHz/S |128|128|287.42|5.99|284.37|5.92|296.81|6.18|488.63|10.18|554.5|11.55|553.75|11.54|
| 128*2/48kHz   |128|256|415.42|8.65|412.37|8.59|425.79|8.87|616.63|12.85|682.48|14.22|681.75|14.2|
| 128*3/48kHz/S |128|256|416.42|8.68|412.37|8.59|424.76|8.85|616.63|12.85|682.47|14.22|680.75|14.18|
| 128*3/48kHz   |128|384|543.42|11.32|540.37|11.26|553.74|11.54|744.63|15.51|810.49|16.89|808.75|16.85|
| 256*2/48kHz/S |256|256|543.42|11.32|540.38|11.26|552.72|11.51|888.63|18.51|954.49|19.89|952.75|19.85|
| 256*2/48kHz   |256|512|799.42|16.65|796.38|16.59|808.69|16.85|1144.62|23.85|1210.48|25.22|1208.75|25.18|
| 256*3/48kHz/S |256|512|799.42|16.65|796.38|16.59|808.67|16.85|1144.62|23.85|1210.47|25.22|1208.75|25.18|
| 256*3/48kHz   |256|768|1055.42|21.99|1052.38|21.92|1064.65|22.18|1400.62|29.18|1466.49|30.55|1464.75|30.52|
| 512*2/48kHz/S |512|512|1055.42|21.99|1052.38|21.92|1064.62|22.18|1640.62|34.18|1706.48|35.55|1704.75|35.52|
| 512*2/48kHz   |512|1024|1567.42|32.65|1564.38|32.59|1576.6|32.85|2152.62|44.85|2218.5|46.22|2216.75|46.18|
| 512*3/48kHz/S |512|1024|1568.42|32.68|1564.38|32.59|1576.58|32.85|2152.62|44.85|2218.48|46.22|2216.75|46.18|
| 512*3/48kHz   |512|1536|2079.42|43.32|2076.38|43.26|2088.55|43.51|2664.62|55.51|2730.5|56.89|2728.75|56.85|
|1024*2/48kHz/S |1024|1024|2079.42|43.32|2075.38|43.24|2088.53|43.51|3192.62|66.51|3258.48|67.89|3257.75|67.87|
|1024*2/48kHz   |1024|2048|3103.42|64.65|3099.38|64.57|3113.5|64.86|4216.62|87.85|4282.47|89.22|4281.75|89.2|
|1024*3/48kHz/S |1024|2048|3103.42|64.65|3100.38|64.59|n.a.|n.a.|4216.62|87.85|4282.5|89.22|4281.75|89.2|
|1024*3/48kHz   |1024|3072|4127.42|85.99|4124.38|85.92|n.a.|n.a.|5240.62|109.18|5306.47|110.55|5257.75|109.54|
|2048*2/48kHz/S |2048|2048|4128.42|86.01|4124.38|85.92|n.a.|n.a.|5336.62|111.18|5354.49|111.55|5353.75|111.54|
|2048*2/48kHz   |2048|4096|6176.42|128.68|6172.38|128.59|n.a.|n.a.|7384.62|153.85|7450.5|155.22|7401.75|154.2|
|2048*3/48kHz/S |2048|4096|6175.42|128.65|6172.38|128.59|n.a.|n.a.|7384.62|153.85|7450.48|155.22|7401.75|154.2|
|2048*3/48kHz   |2048|6144|8224.42|171.34|8220.38|171.26|n.a.|n.a.|9432.62|196.51|9450.5|196.89|9401.75|195.87|


==== Table 2: Latency Overhead ====


Table 2 - Latency measurements minus jackd reported latency
^ ^HDA 1^^HDA 2^^HDA 3^^USB 1^^USB 2^^USB 3^^
^ ^frames^ms^frames^ms^frames^ms^frames^ms^frames^ms^frames^ms^^
|  64*2/48kHz/S |32.42|0.68|28.37|0.59|41.9|0.87|184.63|3.85|250.48|5.22|249.75|5.2|
|  64*2/48kHz   |32.42|0.68|28.38|0.59|41.88|0.87|184.63|3.85|250.48|5.22|249.75|5.2|
|  64*3/48kHz/S |31.42|0.65|28.38|0.59|40.85|0.85|184.63|3.85|250.47|5.22|249.75|5.2|
|  64*3/48kHz   |31.42|0.65|28.38|0.59|41.83|0.87|184.63|3.85|250.48|5.22|249.75|5.2|
| 128*2/48kHz/S |31.42|0.65|28.37|0.59|40.81|0.85|232.63|4.85|298.5|6.22|297.75|6.2|
| 128*2/48kHz   |31.42|0.65|28.37|0.59|41.79|0.87|232.63|4.85|298.48|6.22|297.75|6.2|
| 128*3/48kHz/S |32.42|0.68|28.37|0.59|40.76|0.85|232.63|4.85|298.47|6.22|296.75|6.18|
| 128*3/48kHz   |31.42|0.65|28.37|0.59|41.74|0.87|232.63|4.85|298.49|6.22|296.75|6.18|
| 256*2/48kHz/S |31.42|0.65|28.38|0.59|40.72|0.85|376.63|7.85|442.49|9.22|440.75|9.18|
| 256*2/48kHz   |31.42|0.65|28.38|0.59|40.69|0.85|376.62|7.85|442.48|9.22|440.75|9.18|
| 256*3/48kHz/S |31.42|0.65|28.38|0.59|40.67|0.85|376.62|7.85|442.47|9.22|440.75|9.18|
| 256*3/48kHz   |31.42|0.65|28.38|0.59|40.65|0.85|376.62|7.85|442.49|9.22|440.75|9.18|
| 512*2/48kHz/S |31.42|0.65|28.38|0.59|40.62|0.85|616.62|12.85|682.48|14.22|680.75|14.18|
| 512*2/48kHz   |31.42|0.65|28.38|0.59|40.6|0.85|616.62|12.85|682.5|14.22|680.75|14.18|
| 512*3/48kHz/S |32.42|0.68|28.38|0.59|40.58|0.85|616.62|12.85|682.48|14.22|680.75|14.18|
| 512*3/48kHz   |31.42|0.65|28.38|0.59|40.55|0.84|616.62|12.85|682.5|14.22|680.75|14.18|
|1024*2/48kHz/S |31.42|0.65|27.38|0.57|40.53|0.84|1144.62|23.85|1210.48|25.22|1209.75|25.2|
|1024*2/48kHz   |31.42|0.65|27.38|0.57|41.5|0.86|1144.62|23.85|1210.47|25.22|1209.75|25.2|
|1024*3/48kHz/S |31.42|0.65|28.38|0.59| | |1144.62|23.85|1210.5|25.22|1209.75|25.2|
|1024*3/48kHz   |31.42|0.65|28.38|0.59| | |1144.62|23.85|1210.47|25.22|1161.75|24.2|
|2048*2/48kHz/S |32.42|0.68|28.38|0.59| | |1240.62|25.85|1258.49|26.22|1257.75|26.2|
|2048*2/48kHz   |32.42|0.68|28.38|0.59| | |1240.62|25.85|1306.5|27.22|1257.75|26.2|
|2048*3/48kHz/S |31.42|0.65|28.38|0.59| | |1240.62|25.85|1306.48|27.22|1257.75|26.2|
|2048*3/48kHz   |32.42|0.68|28.38|0.59| | |1240.62|25.85|1258.5|26.22|1209.75|25.2|

==== Table 3  ====

Table 3 - Latency measurements for USB devices minus jackd reported latency minus one extra period length
^ ^ USB 1^^USB 2^^USB 3^^
^ ^frames^ms^frames^ms^frames^ms^^
|  64*2/48kHz/S |120.63|2.51|186.48|3.89|185.75|3.87|
|  64*2/48kHz   |120.63|2.51|186.48|3.89|185.75|3.87|
|  64*3/48kHz/S |120.63|2.51|186.47|3.88|185.75|3.87|
|  64*3/48kHz   |120.63|2.51|186.48|3.89|185.75|3.87|
| 128*2/48kHz/S |104.63|2.18|170.5|3.55|169.75|3.54|
| 128*2/48kHz   |104.63|2.18|170.48|3.55|169.75|3.54|
| 128*3/48kHz/S |104.63|2.18|170.47|3.55|168.75|3.52|
| 128*3/48kHz   |104.63|2.18|170.49|3.55|168.75|3.52|
| 256*2/48kHz/S |120.63|2.51|186.49|3.89|184.75|3.85|
| 256*2/48kHz   |120.62|2.51|186.48|3.89|184.75|3.85|
| 256*3/48kHz/S |120.62|2.51|186.47|3.88|184.75|3.85|
| 256*3/48kHz   |120.62|2.51|186.49|3.89|184.75|3.85|
| 512*2/48kHz/S |104.62|2.18|170.48|3.55|168.75|3.52|
| 512*2/48kHz   |104.62|2.18|170.5|3.55|168.75|3.52|
| 512*3/48kHz/S |104.62|2.18|170.48|3.55|168.75|3.52|
| 512*3/48kHz   |104.62|2.18|170.5|3.55|168.75|3.52|
|1024*2/48kHz/S |120.62|2.51|186.48|3.89|185.75|3.87|
|1024*2/48kHz   |120.62|2.51|186.47|3.88|185.75|3.87|
|1024*3/48kHz/S |120.62|2.51|186.5|3.89|185.75|3.87|
|1024*3/48kHz   |120.62|2.51|186.47|3.88|137.75|2.87|
|2048*2/48kHz/S |-807.38|-16.82|-789.51|-16.45|-790.25|-16.46|
|2048*2/48kHz   |-807.38|-16.82|-741.5|-15.45|-790.25|-16.46|
|2048*3/48kHz/S |-807.38|-16.82|-741.52|-15.45|-790.25|-16.46|
|2048*3/48kHz   |-807.38|-16.82|-789.5|-16.45|-838.25|-17.46|


===== Plots =====
(click on the image for full original size)

==== Table 1 ====
{{:wiki:jack_latency_tests:table1lin.png?810|
Table 1 - Latency values for six different audio devices: three on-board HDA and three external USB.}}

Same plot with logarithmic time-axis (n = (2^x) with  4<=x<=12 , x ∈ N):
{{:wiki:jack_latency_tests:table1.png?250|Table 1 - Latency values for six different audio devices (log scale): three on-board HDA and three external USB.}}

==== Table 2 ====

{{:wiki:jack_latency_tests:table2lin.png?810|Table 2 - Latency measurements minus jackd reported latency}}

Plot of Table 2 with logarithmic time-axis:
{{:wiki:jack_latency_tests:table2.png?250|Table 2 - Latency measurements minus jackd reported latency (log scale)}}

==== Table 3 ====
{{:wiki:jack_latency_tests:table3.png?810|Table 3 - Latency measurements for USB devices minus jackd reported latency minus one extra period length}}

HDA 1 and USB 1 showing the knee at p=1024 for USB devices: {{:wiki:jack_latency_tests:table3b.png?250|}}


===== Datafiles and scripts =====
The raw data files (CSV) including the gnuplot script to generate these plots is available for download:
{{:wiki:jack_latency_tests:latencyplot.tgz|}}

A script to acquire the data using ''jack_delay'' can the found at ''%%git://rg42.org/latentor%%'' or directly: 
[[http://rg42.org/gitweb/?p=latentor.git;a=snapshot;sf=tgz|latentor.tgz]].