> -----Original Message----- > From: Olivier Matz [mailto:olivier.m...@6wind.com] > Sent: Friday, March 24, 2017 9:05 AM > To: Eads, Gage <gage.e...@intel.com> > Cc: dev@dpdk.org > Subject: Re: [PATCH v3] mempool: remove non-EAL thread note from header > > Hi Gage, > > On Thu, 23 Mar 2017 09:20:58 -0500, Gage Eads <gage.e...@intel.com> > wrote: > > Commit 30e6399892276 ("mempool: support non-EAL thread") added the > > capability for non-EAL threads to use the mempool library. This commit > > removes the note indicating that the mempool library cannot be used > > safely by non-EAL threads. > > > > Also, fix a typo. > > > > Signed-off-by: Gage Eads <gage.e...@intel.com> > > --- > > v2: Changed commit message to referenced commit 30e63998 instead of > > 4b5062755 > > v3: Fix checkpatch error > > > > lib/librte_mempool/rte_mempool.h | 6 +----- > > 1 file changed, 1 insertion(+), 5 deletions(-) > > > > diff --git a/lib/librte_mempool/rte_mempool.h > > b/lib/librte_mempool/rte_mempool.h > > index 991feaa..b1186fd 100644 > > --- a/lib/librte_mempool/rte_mempool.h > > +++ b/lib/librte_mempool/rte_mempool.h > > @@ -53,11 +53,7 @@ > > * > > * Note: the mempool implementation is not preemptable. A lcore must > > * not be interrupted by another task that uses the same mempool > > - * (because it uses a ring which is not preemptable). Also, mempool > > - * functions must not be used outside the DPDK environment: for > > - * example, in linuxapp environment, a thread that is not created by > > - * the EAL must not use mempools. This is due to the per-lcore cache > > - * that won't work as rte_lcore_id() will not return a correct value. > > + * (because it uses a ring which is not preemptible). > > */ > > > > #include <stdio.h> > > I agree the comment is not correct today. But I think we should still > highlight > that usual functions [ex: rte_mempool_get(), rte_mempool_put()] won't work > when called on a non-EAL thread.
My understanding is that non-EAL threads can call those functions, but their performance will suffer since they go directly to the underlying ring. Is that correct? > > Maybe it could be reworded in that way: > > """ > Note: the mempool implementation is not preemptable. A lcore must not be > interrupted by another task that uses the same mempool (because it uses a > ring > which is not preemptible). Also, usual mempool functions like > rte_mempool_get() or rte_mempool_put() are designed to be called from an > EAL thread due to the internal per-lcore cache. When using a mempool from a > non-EAL thread, a user cache has to be provided to > rte_mempool_generic_get() or rte_mempool_generic_put(). > """ > > What do you think? Agreed, this looks better. If indeed non-EAL threads can call rte_mempool_get() and _put(), perhaps the last sentence can be reworked like so? Due to the lack of caching, rte_mempool_get() or rte_mempool_put() performance will suffer when called by non-EAL threads. Instead, non-EAL threads should call rte_mempool_generic_get() or rte_mempool_generic_put() with a user cache created with rte_mempool_cache_create(). > > Thanks, > Olivier
