snf_rss_params Struct Reference
[Receive-Side Scaling (RSS)]

Data Fields
enum snf_rss_params_mode	mode
union {
enum snf_rss_mode_flags   rss_flags
snf_rss_mode_function   rss_function
}	params

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Detailed Description

When using multiple rings, users can either let Sniffer how to partition the flows of incoming packets or control the hashing using specific RSS modes. The following modes are available.

• None: rss_params is NULL in snf_open. When no RSS mode is explicitly specified, users let the implementation chose an RSS strategy that best matches the revision of the Myri-10G NIC. Unless a specific hashing strategy is required, this approach is best in terms of performance-portability.

• Flag-based: rss_params sets mode to SNF_RSS_FLAGS. This mode allows users to functionally specify which parts of a packet are significant in the RSS hashing process. A functional specification leaves enough room for the Sniffer implementation to move part or all of the hash computation between hardware, firmware and software.

• Function-based: rss_params sets mode to SNF_RSS_FUNCTION. This mode guarantees the most flexibility for the user but forces the hashing to be serialized in software (note that the current generation NICs do not necessarily take a very large performance hit compared to the two other RSS modes). This approach may be required if the flag-based approach isn't flexible enough. For example, some users may require that flow affinity be maintained according to an encapsulated TCP/IP header. See snf_rss_mode_function for more details.

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Field Documentation

enum snf_rss_params_mode snf_rss_params::mode

RSS mode

enum snf_rss_mode_flags snf_rss_params::rss_flags

RSS parameters for SNF_RSS_FLAGS

struct snf_rss_mode_function snf_rss_params::rss_function

RSS params for SNF_RSS_FUNCTION

union { ... } snf_rss_params::params

RSS parameter settings, according to the mode that is selected

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26 October 2010 Sniffer10G 1.0.2_pcap1.1.1