RE: [PATCH v6] enhance NUMA affinity heuristic

["You, KaisenX" <kaisenx.you@intel.com>]

> -----Original Message-----
> From: Thomas Monjalon <thomas@monjalon.net>
> Sent: 2023年4月27日 14:58
> To: You, KaisenX <kaisenx.you@intel.com>
> Cc: dev@dpdk.org; Zhou, YidingX <yidingx.zhou@intel.com>;
> david.marchand@redhat.com; Matz, Olivier <olivier.matz@6wind.com>;
> ferruh.yigit@amd.com; Burakov, Anatoly <anatoly.burakov@intel.com>; You,
> KaisenX <kaisenx.you@intel.com>; stable@dpdk.org
> Subject: Re: [PATCH v6] enhance NUMA affinity heuristic
> 
> 25/04/2023 07:16, Kaisen You:
> > Trying to allocate memory on the first detected numa node,it has less
> > chance to find some memory actually available rather than on the main
> > lcore numa node (especially when the DPDK application is started only
> > on one numa node).
> 
> You didn't change the explanations here as discussed previously.
> 
> >
> > Fixes: 8b0a1b8cb481 ("eal: stop using pthread for lcores and control
> > threads")
> > Fixes: 770d41bf3309 ("malloc: fix allocation with unknown socket ID")
> > Cc: stable@dpdk.org
> >
> > Signed-off-by: David Marchand <david.marchand@redhat.com>
> > Signed-off-by: Kaisen You <kaisenx.you@intel.com>
> >
> > ---
> > Changes since v5:
> > - Add comments to the code,
> >
> > Changes since v4:
> > - mod the patch title,
> >
> > Changes since v3:
> > - add the assignment of socket_id in thread initialization,
> >
> > Changes since v2:
> > - add uncommitted local change and fix compilation,
> >
> > Changes since v1:
> > - accomodate for configurations with main lcore running on multiples
> >   physical cores belonging to different numa,
> > ---
> >  lib/eal/common/eal_common_thread.c | 4 ++++
> >  lib/eal/common/malloc_heap.c       | 6 ++++++
> >  2 files changed, 10 insertions(+)
> >
> > diff --git a/lib/eal/common/eal_common_thread.c
> > b/lib/eal/common/eal_common_thread.c
> > index 079a385630..d65bfe251b 100644
> > --- a/lib/eal/common/eal_common_thread.c
> > +++ b/lib/eal/common/eal_common_thread.c
> > @@ -252,6 +252,10 @@ static int ctrl_thread_init(void *arg)
> >  	struct rte_thread_ctrl_params *params = arg;
> >
> >  	__rte_thread_init(rte_lcore_id(), cpuset);
> > +	/* set the value of the per-core variable _socket_id.
> > +	 * Convenient for threads to find memory.
> > +	 */
> 
> That's an useless comment.
> We want to know WHY you are setting to SOCKET_ID_ANY.
> 
> > +	RTE_PER_LCORE(_socket_id) = SOCKET_ID_ANY;
> >  	params->ret = rte_thread_set_affinity_by_id(rte_thread_self(),
> cpuset);
> >  	if (params->ret != 0) {
> >  		__atomic_store_n(&params->ctrl_thread_status,
> > diff --git a/lib/eal/common/malloc_heap.c
> > b/lib/eal/common/malloc_heap.c index d25bdc98f9..a624f08cf7 100644
> > --- a/lib/eal/common/malloc_heap.c
> > +++ b/lib/eal/common/malloc_heap.c
> > @@ -716,6 +716,12 @@ malloc_get_numa_socket(void)
> >  		if (conf->socket_mem[socket_id] != 0)
> >  			return socket_id;
> >  	}
> > +	/* Trying to allocate memory on the main lcore numa node.
> > +	 * especially when the DPDK application is started only on one numa
> node.
> > +	 */
> > +	socket_id = rte_lcore_to_socket_id(rte_get_main_lcore());
> > +	if (socket_id != (unsigned int)SOCKET_ID_ANY)
> > +		return socket_id;
> 
> You should explain why we could reach this point, i.e. SOCKET_ID_ANY.

I'm sorry I didn't reply to you in time due to COVID-19 infection, I will send the v7 
version as soon as possible to fix the problem you mentioned.
> 
> >
> >  	return rte_socket_id_by_idx(0);
> >  }
> 
>