> From: Jim Thompson [mailto:jim at netgate.com] > Sent: Tuesday, January 20, 2015 10:48 AM > To: Ananyev, Konstantin > Cc: Thomas Monjalon; dev at dpdk.org > Subject: Re: [dpdk-dev] [PATCH v2 17/17] libte_acl: remove unused macros. > > > On Jan 20, 2015, at 4:09 AM, Ananyev, Konstantin <konstantin.ananyev at > intel.com> wrote: > > Hi Thomas, > > > -----Original Message----- > From: Thomas Monjalon [mailto:thomas.monjalon at 6wind.com] > Sent: Monday, January 19, 2015 5:18 PM > To: Ananyev, Konstantin > Cc: dev at dpdk.org > Subject: Re: [dpdk-dev] [PATCH v2 17/17] libte_acl: remove unused macros. > > 2015-01-12 19:16, Konstantin Ananyev: > > /* > + * ACL RT structure is a set of multibit tries (with stride == 8) > + * represented by an array of transitions. The next position is calculated > + * based on the current position and the input byte. > + * Each transition is 64 bit value with the following format: > + * | node_type_specific : 32 | node_type : 3 | node_addr : 29 | > + * For all node types except RTE_ACL_NODE_MATCH, node_addr is an index > + * to the start of the node in the transtions array. > + * Few different node types are used: > + * RTE_ACL_NODE_MATCH: > + * node_addr value is and index into an array that contains the return value > + * and its priority for each category. > + * Upper 32 bits of the transtion value are not used for that node type. > + * RTE_ACL_NODE_QRANGE: > + * that node consist of up to 5 transitions. > + * Upper 32 bits are interpreted as 4 signed character values which > + * are ordered from smallest(INT8_MIN) to largest (INT8_MAX). > + * These values define 5 ranges: > + * INT8_MIN <= range[0] ?<= ((int8_t *)&transition)[4] > + * ((int8_t *)&transition)[4] < range[1] <= ((int8_t *)&transition)[5] > + * ((int8_t *)&transition)[5] < range[2] <= ((int8_t *)&transition)[6] > + * ((int8_t *)&transition)[6] < range[3] <= ((int8_t *)&transition)[7] > + * ((int8_t *)&transition)[7] < range[4] <= INT8_MAX > + * So for input byte value within range[i] i-th transition within that node > + * will be used. > + * RTE_ACL_NODE_SINGLE: > + * always transitions to the same node regardless of the input value. > + * RTE_ACL_NODE_DFA: > + * that node consits of up to 256 transitions. > + * In attempt to conserve space all transitions are divided into 4 > consecutive > + * groups, by 64 transitions per group: > + * group64[i] contains transitions[i * 64, .. i * 64 + 63]. > + * Upper 32 bits are interpreted as 4 unsigned character values one per > group, > + * which contain index to the start of the given group within the node. > + * So to calculate transition index within the node for given input byte > value: > + * input_byte - ((uint8_t *)&transition)[4 + input_byte / 64]. > + */ > > It's maybe an error. You were only supposed to remove some macros in this > patch. > > Ah yes, I added some comments about ACL internal layout. > Thought it might be useful. > Forgot to add it into patch description. > Are you saying I need to split it into 2 patches, or it is ok like that? > > it?s great info, but it should probably go > in?doc/guides/prog_guide/packet_classif_access_ctrl.rst.
Well, I think it is a good practise to have some brief description of the internal structure in the header file. Same as rte_ring.h, rte_mempool.h, rte_timer.h. When I'll start doc updating, I can put some sort of internal structure description into PG too, though not sure it is worth it.
