Hi Gage, On Wed, 29 Mar 2017 15:30:49 +0000, "Eads, Gage" <gage.e...@intel.com> wrote: > > -----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?
Yes, that's more correct than what I wrote :) > > > > > 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(). Looks good, thanks! Olivier > > > > > Thanks, > > Olivier
