On Fri, 18 Oct, 2019, 3:40 pm Xueming(Steven) Li, <xuemi...@mellanox.com> wrote:
> > -----Original Message----- > > From: Jerin Jacob <jerinjac...@gmail.com> > > Sent: Friday, October 18, 2019 12:41 AM > > To: Xueming(Steven) Li <xuemi...@mellanox.com> > > Cc: Olivier Matz <olivier.m...@6wind.com>; Andrew Rybchenko > > <arybche...@solarflare.com>; dpdk-dev <dev@dpdk.org>; Asaf Penso > > <as...@mellanox.com>; Ori Kam <or...@mellanox.com>; Stephen > > Hemminger <step...@networkplumber.org> > > Subject: Re: [dpdk-dev] [RFC] mempool: introduce indexed memory pool > > > > On Thu, Oct 17, 2019 at 6:43 PM Xueming(Steven) Li > > <xuemi...@mellanox.com> wrote: > > > > > > > -----Original Message----- > > > > From: Jerin Jacob <jerinjac...@gmail.com> > > > > Sent: Thursday, October 17, 2019 3:14 PM > > > > To: Xueming(Steven) Li <xuemi...@mellanox.com> > > > > Cc: Olivier Matz <olivier.m...@6wind.com>; Andrew Rybchenko > > > > <arybche...@solarflare.com>; dpdk-dev <dev@dpdk.org>; Asaf Penso > > > > <as...@mellanox.com>; Ori Kam <or...@mellanox.com> > > > > Subject: Re: [dpdk-dev] [RFC] mempool: introduce indexed memory pool > > > > > > > > On Thu, Oct 17, 2019 at 12:25 PM Xueming Li <xuemi...@mellanox.com> > > wrote: > > > > > > > > > > Indexed memory pool manages memory entries by index, allocation > > > > > from pool returns both memory pointer and index(ID). users save ID > > > > > as u32 or less(u16) instead of traditional 8 bytes pointer. Memory > > > > > could be retrieved from pool or returned to pool later by index. > > > > > > > > > > Pool allocates backend memory in chunk on demand, pool size grows > > > > > dynamically. Bitmap is used to track entry usage in chunk, thus > > > > > management overhead is one bit per entry. > > > > > > > > > > Standard rte_malloc demands malloc overhead(64B) and minimal data > > > > > size(64B). This pool aims to such cost saving also pointer size. > > > > > For scenario like creating millions of rte_flows each consists of > > > > > small pieces of memories, the difference is huge. > > > > > > > > > > Like standard memory pool, this lightweight pool only support > > > > > fixed size memory allocation. Pools should be created for each > > > > > different size. > > > > > > > > > > To facilitate memory allocated by index, a set of ILIST_XXX macro > > > > > defined to operate entries as regular LIST. > > > > > > > > > > By setting entry size to zero, pool can be used as ID generator. > > > > > > > > > > Signed-off-by: Xueming Li <xuemi...@mellanox.com> > > > > > --- > > > > > lib/librte_mempool/Makefile | 3 +- > > > > > lib/librte_mempool/rte_indexed_pool.c | 289 > > +++++++++++++++++++++ > > > > > lib/librte_mempool/rte_indexed_pool.h | 224 ++++++++++++++++ > > > > > > > > Can this be abstracted over the driver interface instead of creating > a new > > APIS? > > > > ie using drivers/mempool/ > > > > > > The driver interface manage memory entries with pointers, while this > api > > uses u32 index as key... > > > > I see. As a use case, it makes sense to me. > > > Have you checked the possibility reusing/extending > > lib/librte_eal/common/include/rte_bitmap.h for bitmap management, > > instead of rolling a new one? > > Yes, the rte_bitmap designed for fixed bitmap size, to grow, have to copy > almost entire bitmap(array1+array2). > This pool distribute array2 into each trunk, and the trunk array actually > plays the array1 role. > When growing, just grow array1 which is smaller, no touch to existing > array2 in each trunk. > IMO, Growing bit map is generic problem so moving bitmap management logic to common place will be usefull for other libraries in future. My suggestion would be to enchanse rte_bitmap to support dynamic bitmap through new APIs. > The map_xxx() naming might confused people, I'll make following change in > next version: > map_get()/map_set(): only used once and the code is simple, move > code into caller. > map_is_empty()/map_clear()/ : unused, remove > map_clear_any(): relative simple, embed into caller. >
