Configuring Gigabit Ethernet Parameters
Understanding the Gigabit Ethernet Parameters
in all. One of the two parameters specifies the number of data buffers that the card must transmit (or receive) before interrupting and the other specifies the number of system clock ticks that must elapse before interrupting.
The four tuning parameters are summarized in the following table.
Table | Performance Tuning Parameters |
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Name |
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send_max_bufs |
| 1 | – 128 | 16 | (for gelan) | # of buffers |
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| 10 | (for igelan) |
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recv_max_bufs |
| 1 | – 256 | 1 |
| # of buffers |
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send_coal_ticks |
| 0 | – 10000000 | 1000 (for gelan) | microseconds | |
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| 150 (for igelan) |
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recv_coal_ticks |
| 0 | – 10000000 | 0 |
| microseconds |
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A send interrupt is generated by the card to the host when either:
•the number of buffers sent by the card since the previous send interrupt equals send_max_bufs
or
•the time that has elapsed since the previous send interrupt equals send_coal_ticks (a value of zero disables
whichever occurs first.
A receive interrupt is generated by the card to the host when either:
•the number of frames received by the card since the previous receive interrupt equals recv_max_bufs
or
•the time that has elapsed since the previous receive interrupt equals recv_coal_ticks (a value of zero disables
whichever occurs first.
14 | Chapter 2 |