> -----Original Message----- > From: Thomas Monjalon [mailto:thomas.monjalon at 6wind.com] > Sent: Thursday, September 8, 2016 10:36 AM > To: Gowrishankar Muthukrishnan <gowrishankar.m at linux.vnet.ibm.com> > Cc: dev at dpdk.org; Dumitrescu, Cristian <cristian.dumitrescu at intel.com>; > Chao Zhu <chaozhu at linux.vnet.ibm.com>; Richardson, Bruce > <bruce.richardson at intel.com>; Ananyev, Konstantin > <konstantin.ananyev at intel.com>; Pradeep <pradeep at us.ibm.com> > Subject: Re: [dpdk-dev] [PATCH v6 9/9] table: align rte table hash structs for > cache line size > > 2016-08-31 17:29, Dumitrescu, Cristian: > > From: Gowrishankar Muthukrishnan > > > rte table hash structs rte_bucket_4_8, rte_bucket_4_16 and > > > rte_bucket_4_32 have > > > to be cache aligned as required by their corresponding hash create > functions > > > rte_table_hash_create_key8_lru etc. > > > > Hi Gowrishankar, > > > > My understanding is you are trying to work around the check invoked by > the hash table create functions that verifies the size of the bucket header > structure is a multiple of the cache line, right? > > > > Given that the size of this structure is 1x, 2x or 3x times 64 bytes, the > > check > passes on IA CPUs (cache line of 64 bytes; explicit alignment to cache line > size > is not needed in order to make the size of the structure a multiple of cache > line), but not on PPC CPUs (cache line of 128 bytes), correct? > > > > I don't think your proposal provides the best way to fix this issue, since > your code leads to a considerable increase in the memory consumption used > per bucket in most cases: > > - 100% more memory for 8-byte key hash table > > - 0% more for 16-byte key hash table (code does not fix anything, > explicit alignment is not needed) > > - 50% more for 32-byte key hash table > > > > I suggest you simply change the check: instead of validating this data > structure is a multiple of cache line size, validate it is a multiple of 64 > bytes. > > Any news please? > The whole series is blocked for this patch. > Should we expect a v7?
Yes, I think we should. Small fix for a considerable benefit.
