Hi, Adrien Mazarguil > -----Original Message----- > From: Adrien Mazarguil [mailto:adrien.mazarg...@6wind.com] > Sent: Friday, May 12, 2017 5:13 PM > To: Zhao1, Wei <wei.zh...@intel.com> > Cc: dev@dpdk.org; Xing, Beilei <beilei.x...@intel.com>; Lu, Wenzhuo > <wenzhuo...@intel.com> > Subject: Re: [dpdk-dev] [PATCH v5 19/26] app/testpmd: add item raw to flow > command > > Hi Wei, > > On Thu, May 11, 2017 at 06:53:52AM +0000, Zhao1, Wei wrote: > > Hi, Adrien > > > > > -----Original Message----- > > > From: dev [mailto:dev-boun...@dpdk.org] On Behalf Of Adrien > > > Mazarguil > > > Sent: Wednesday, December 21, 2016 10:52 PM > > > To: dev@dpdk.org > > > Subject: [dpdk-dev] [PATCH v5 19/26] app/testpmd: add item raw to > > > flow command > > > > > > Matches arbitrary byte strings with properties: > > > > > > - relative: look for pattern after the previous item. > > > - search: search pattern from offset (see also limit). > > > - offset: absolute or relative offset for pattern. > > > - limit: search area limit for start of pattern. > > > - length: pattern length. > > > - pattern: byte string to look for. > > > > > > Signed-off-by: Adrien Mazarguil <adrien.mazarg...@6wind.com> > > > Acked-by: Olga Shern <ol...@mellanox.com> > [...] > > #define ITEM_RAW_PATTERN_SIZE 36 > > > > The size of NIC i350 flex byte filter can accommodate the max length > > size of 128 byte, and the reason to Define it as 36 is ?If it is the max > > length > of pattern, maybe 128 is more appropriate? > > Maybe I have not understand your purpose. > > > > Thank you. > > It's more or less an arbitrary compromise due to various limitations. > > Once parsed, the result of an entire command is stored in a fixed buffer of > size CMDLINE_PARSE_RESULT_BUFSIZE (8192). Each parsed token ends up > somewhere in that buffer. > > Each flow item always consumes sizeof(struct rte_flow_item) + sizeof(struct > rte_flow_item_xxx) * 3 (spec, last and mask) + alignment constraints. > > For the raw item, this makes at least: > > (sizeof(rte_flow_item) + > (sizeof(rte_flow_item_raw) + ITEM_RAW_PATTERN_SIZE) * 3) > /* (32 + (12 + 36) * 3) => 176 bytes */ > > Because space is always consumed regardless of the size of the byte string to > match for implementation reasons, there is a chance to fill the buffer too > quickly with a larger ITEM_RAW_PATTERN_SIZE. > > Also, this does not prevent users from specifying larger raw patterns (even > larger than 128) by combining them, e.g.: > > flow create 0 > pattern eth / raw relative is 1 pattern is foobar / > raw relative is 1 pattern is barbaz / end > actions queue index 42 / end > > Such a pattern ends up matching a single "foobarbarbaz" string. > > To summarize, it is only due to testpmd limitations. Even without PMD > support for combination, the current ability to provide 36 bytes of raw data > to match per specified item is plenty to validate basic functionality. We'll > improve testpmd eventually. >
Thank you for your detailed explanation. Igb flex byte filter will support for that type combination for raw item. But this testpmd limitation will make trouble for users and tester. > -- > Adrien Mazarguil > 6WIND
