This describes how to configure the onboard SDRAM of SmartNICs using the
SDRAMSplit parameter.
SDRAMSplit parameter
Onboard SDRAM of SmartNICs running on a flow management image is used for storing the flow
table and for frame buffering. The SDRAM memory split between frame buffering and flow
management is configurable using the
SDRAMSplit parameter in the
ntservice.ini
file. By default, it is configured to have limited frame buffering / a
lot of flows. The following is the default configuration in the
ntservice.ini file.
SDRAMSplit=[Buffer=12.5, Flowtable=87.5]
By default, 10.5 Gbytes
(87.5% of 12 Gbytes) are reserved for the flow table and 1.5 Gbytes (12.5% of 12 Gbytes) are
reserved for frame buffering on the NT200A02. By default, 7 Gbytes (87.5% of 8 Gbytes) are
reserved for the flow table and 1 Gbyte (12.5% of 8 Gbytes) is reserved for frame buffering
on the NT100A01. If received frames are dropped due to traffic burst, it is recommended to
adjust the
SDRAMSplit values to have larger frame buffering / less
flows.
Buffering time and flow table capacity
The table below shows expected buffering time at full line rate and expected flow table
capacity based on the onboard SDRAM split configuration examples for the NT200A02.
| SDRAMSplit
values in ntservice.ini |
Frame
buffering |
Flow table |
| SDRAM size in Gbytes |
Buffering in milliseconds at
100 Gbit/s |
SDRAM size in Gbytes |
Number of flows |
| [Buffer=12.5, Flowtable=87.5] |
1.5 |
130 |
10.5 |
140 M |
| [Buffer=50, Flowtable=50] |
6.0 |
510 |
6.0 |
80 M |
| [Buffer=75, Flowtable=25] |
9.0 |
770 |
3.0 |
40 M |
| [Buffer=87.5, Flowtable=12.5] |
10.5 |
900 |
1.5 |
20 M |
The table below shows expected buffering time at full line rate and expected flow
table capacity based on the onboard SDRAM split configuration examples for the NT100A01.
| SDRAMSplit
values in ntservice.ini |
Frame
buffering |
Flow table |
| SDRAM size in Gbytes |
Buffering in milliseconds at
100 Gbit/s |
SDRAM size in Gbytes |
Number of flows |
| [Buffer=12.5, Flowtable=87.5] |
1.0 |
90 |
7.0 |
93 M |
| [Buffer=50, Flowtable=50] |
4.0 |
350 |
4.0 |
53 M |
| [Buffer=68.75, Flowtable=31.25] |
5.5 |
500 |
2.5 |
33 M |
| [Buffer=87.5, Flowtable=12.5] |
7.0 |
600 |
1.0 |
13 M |
See
DN-0449 for more information about the
SDRAMSplit parameter in the
ntservice.ini
file.