Re: [PATCH 1/6] dma/skeleton: use rte thread API

[Tyler Retzlaff <roretzla@linux.microsoft.com>]

On Tue, Apr 18, 2023 at 10:19:15AM +0100, Bruce Richardson wrote:
> On Fri, Mar 17, 2023 at 03:34:15PM -0700, Tyler Retzlaff wrote:
> > Update driver to use rte thread API where available instead of pthread
> > as a prerequisite to removing pthread stubs on Windows.
> > 
> > Signed-off-by: Tyler Retzlaff <roretzla@linux.microsoft.com>
> > ---
> >  drivers/dma/skeleton/skeleton_dmadev.c | 15 ++++++++-------
> >  drivers/dma/skeleton/skeleton_dmadev.h |  4 ++--
> >  2 files changed, 10 insertions(+), 9 deletions(-)
> > 
> > diff --git a/drivers/dma/skeleton/skeleton_dmadev.c b/drivers/dma/skeleton/skeleton_dmadev.c
> > index daf35ec..2ec10db 100644
> > --- a/drivers/dma/skeleton/skeleton_dmadev.c
> > +++ b/drivers/dma/skeleton/skeleton_dmadev.c
> > @@ -5,6 +5,8 @@
> >  #include <inttypes.h>
> >  #include <stdlib.h>
> >  
> > +#include <pthread.h>
> > +
> 
> Curious as to why this is needed here. Does rte_thread.h not include all
> needed threading dependencies?
> [Self-answer] I assume this is for pthread_cancel below, right?

yes, pthread_cancel has no equivalent in the EAL. windows can't easily
provide anything that would behave the same, but pthread_cancel is kind
of awful anyway.

it's something that i'm thinking about but haven't got a good solution
for. so for now any code that uses it remains.

> 
> 
> >  #include <bus_vdev_driver.h>
> >  #include <rte_cycles.h>
> >  #include <rte_eal.h>
> > @@ -53,7 +55,7 @@
> >  	return 0;
> >  }
> >  
> > -static void *
> > +static uint32_t
> >  cpucopy_thread(void *param)
> >  {
> >  #define SLEEP_THRESHOLD		10000
> > @@ -81,7 +83,7 @@
> >  		(void)rte_ring_enqueue(hw->desc_completed, (void *)desc);
> >  	}
> >  
> > -	return NULL;
> > +	return 0;
> >  }
> >  
> >  static void
> > @@ -126,7 +128,7 @@
> >  	rte_mb();
> >  
> >  	snprintf(name, sizeof(name), "dma_skel_%d", dev->data->dev_id);
> > -	ret = rte_ctrl_thread_create(&hw->thread, name, NULL,
> > +	ret = rte_thread_create_control(&hw->thread, name, NULL,
> >  				     cpucopy_thread, dev);
> >  	if (ret) {
> >  		SKELDMA_LOG(ERR, "Start cpucopy thread fail!");
> > @@ -135,8 +137,7 @@
> >  
> >  	if (hw->lcore_id != -1) {
> >  		cpuset = rte_lcore_cpuset(hw->lcore_id);
> > -		ret = pthread_setaffinity_np(hw->thread, sizeof(cpuset),
> > -					     &cpuset);
> > +		ret = rte_thread_get_affinity_by_id(hw->thread, &cpuset);
> >  		if (ret)
> >  			SKELDMA_LOG(WARNING,
> >  				"Set thread affinity lcore = %d fail!",
> > @@ -154,8 +155,8 @@
> >  	hw->exit_flag = true;
> >  	rte_delay_ms(1);
> >  
> > -	(void)pthread_cancel(hw->thread);
> > -	pthread_join(hw->thread, NULL);
> > +	(void)pthread_cancel((pthread_t)hw->thread.opaque_id);
> > +	rte_thread_join(hw->thread, NULL);
> >  
> 
> Is there no rte_* equivalent to pthread_cancel? Will that cause issues
> later?

there isn't because windows can't really do what it is doing sensibly.
in part it's because of how it is influences how other posix calls
behave.

> 
> >  	return 0;
> >  }
> > diff --git a/drivers/dma/skeleton/skeleton_dmadev.h b/drivers/dma/skeleton/skeleton_dmadev.h
> > index 6f89400..8670a68 100644
> > --- a/drivers/dma/skeleton/skeleton_dmadev.h
> > +++ b/drivers/dma/skeleton/skeleton_dmadev.h
> > @@ -5,9 +5,9 @@
> >  #ifndef SKELETON_DMADEV_H
> >  #define SKELETON_DMADEV_H
> >  
> > -#include <pthread.h>
> >  
> >  #include <rte_ring.h>
> > +#include <rte_thread.h>
> >  
> >  #define SKELDMA_ARG_LCORE	"lcore"
> >  
> > @@ -21,7 +21,7 @@ struct skeldma_desc {
> >  struct skeldma_hw {
> >  	int lcore_id; /* cpucopy task affinity core */
> >  	int socket_id;
> > -	pthread_t thread; /* cpucopy task thread */
> > +	rte_thread_t thread; /* cpucopy task thread */
> >  	volatile int exit_flag; /* cpucopy task exit flag */
> >  
> >  	struct skeldma_desc *desc_mem;
> > -- 
> > 1.8.3.1
> >