> -----Original Message-----
> From: Olivier MATZ [mailto:olivier.matz at 6wind.com]
> Sent: Wednesday, February 11, 2015 1:45 AM
> To: Liang, Cunming; dev at dpdk.org
> Subject: Re: [dpdk-dev] [PATCH v4 17/17] timer: add support to non-EAL thread
>
> Hi,
>
> On 02/02/2015 03:02 AM, Cunming Liang wrote:
> > Allow to setup timers only for EAL (lcore) threads (__lcore_id <
> MAX_LCORE_ID).
> > E.g. ? dynamically created thread will be able to reset/stop timer for lcore
> thread,
> > but it will be not allowed to setup timer for itself or another non-lcore
> > thread.
> > rte_timer_manage() for non-lcore thread would simply do nothing and return
> straightway.
> >
> > Signed-off-by: Cunming Liang <cunming.liang at intel.com>
> > ---
> > lib/librte_timer/rte_timer.c | 40 +++++++++++++++++++++++++++++++------
> ---
> > lib/librte_timer/rte_timer.h | 2 +-
> > 2 files changed, 32 insertions(+), 10 deletions(-)
> >
> > diff --git a/lib/librte_timer/rte_timer.c b/lib/librte_timer/rte_timer.c
> > index 269a992..601c159 100644
> > --- a/lib/librte_timer/rte_timer.c
> > +++ b/lib/librte_timer/rte_timer.c
> > @@ -79,9 +79,10 @@ static struct priv_timer priv_timer[RTE_MAX_LCORE];
> >
> > /* when debug is enabled, store some statistics */
> > #ifdef RTE_LIBRTE_TIMER_DEBUG
> > -#define __TIMER_STAT_ADD(name, n) do { \
> > - unsigned __lcore_id = rte_lcore_id(); \
> > - priv_timer[__lcore_id].stats.name += (n); \
> > +#define __TIMER_STAT_ADD(name, n) do {
> > \
> > + unsigned __lcore_id = rte_lcore_id(); \
> > + if (__lcore_id < RTE_MAX_LCORE) \
> > + priv_timer[__lcore_id].stats.name += (n); \
> > } while(0)
> > #else
> > #define __TIMER_STAT_ADD(name, n) do {} while(0)
> > @@ -127,15 +128,26 @@ timer_set_config_state(struct rte_timer *tim,
> > unsigned lcore_id;
> >
> > lcore_id = rte_lcore_id();
> > + if (lcore_id >= RTE_MAX_LCORE)
> > + lcore_id = LCORE_ID_ANY;
>
> Is this still valid?
> In my understanding, rte_lcore_id() was returning the core id or
> LCORE_ID_ANY if it's a non-EAL thread.
[LCM] It's a nice to have one, in case lcore_id got an invalid number.
We can add a assert to replace these two line.
>
> >
> > /* wait that the timer is in correct status before update,
> > * and mark it as being configured */
> > while (success == 0) {
> > prev_status.u32 = tim->status.u32;
> >
> > + /*
> > + * prevent race condition of non-EAL threads
> > + * to update the timer. When 'owner == LCORE_ID_ANY',
> > + * it means updated by a non-EAL thread.
> > + */
> > + if (lcore_id == (unsigned)LCORE_ID_ANY &&
> > + (uint16_t)lcore_id == prev_status.owner)
> > + return -1;
> > +
>
> Are you sure this is required?
>
> I think prev_status.owner can be LCORE_ID_ANY only in config state,
> as a timer cannot be scheduled on a non-EAL thread. And there is
> already a test that returns -1 if state is CONFIG.
[LCM] Good point, whenever prev_status.owner == LCORE_ID_ANY, the
prev_status.state must be RTE_TIMER_CONFIG.
Make sense to me to remove the condition check.
>
>
> > /* timer is running on another core, exit */
> > if (prev_status.state == RTE_TIMER_RUNNING &&
> > - (unsigned)prev_status.owner != lcore_id)
> > + prev_status.owner != (uint16_t)lcore_id)
> > return -1;
> >
> > /* timer is being configured on another core */
> > @@ -366,9 +378,13 @@ __rte_timer_reset(struct rte_timer *tim, uint64_t
> expire,
> >
> > /* round robin for tim_lcore */
> > if (tim_lcore == (unsigned)LCORE_ID_ANY) {
> > - tim_lcore = rte_get_next_lcore(priv_timer[lcore_id].prev_lcore,
> > - 0, 1);
> > - priv_timer[lcore_id].prev_lcore = tim_lcore;
> > + if (lcore_id < RTE_MAX_LCORE) {
>
> if (lcore_id != LCORE_ID_ANY) ?
[LCM] Accept.
>
>
> > + tim_lcore = rte_get_next_lcore(
> > + priv_timer[lcore_id].prev_lcore,
> > + 0, 1);
> > + priv_timer[lcore_id].prev_lcore = tim_lcore;
> > + } else
> > + tim_lcore = rte_get_next_lcore(LCORE_ID_ANY, 0, 1);
>
> I think the following line:
> tim_lcore = rte_get_next_lcore(LCORE_ID_ANY, 0, 1);
> Will return the first enabled core.
>
> Maybe using rte_get_master_lcore() is clearer?
[LCM] It doesn't expect must to be a master lcore.
Any available lcore is fine, so I think make sense to just use the first
enabled core.
>
>
>
> > }
> >
> > /* wait that the timer is in correct status before update,
> > @@ -378,7 +394,8 @@ __rte_timer_reset(struct rte_timer *tim, uint64_t
> expire,
> > return -1;
> >
> > __TIMER_STAT_ADD(reset, 1);
> > - if (prev_status.state == RTE_TIMER_RUNNING) {
> > + if (prev_status.state == RTE_TIMER_RUNNING &&
> > + lcore_id < RTE_MAX_LCORE) {
>
> if (lcore_id != LCORE_ID_ANY) ?
>
>
> > priv_timer[lcore_id].updated = 1;
> > }
> >
> > @@ -455,7 +472,8 @@ rte_timer_stop(struct rte_timer *tim)
> > return -1;
> >
> > __TIMER_STAT_ADD(stop, 1);
> > - if (prev_status.state == RTE_TIMER_RUNNING) {
> > + if (prev_status.state == RTE_TIMER_RUNNING &&
> > + lcore_id < RTE_MAX_LCORE) {
>
> if (lcore_id != LCORE_ID_ANY) ?
>
>
> > priv_timer[lcore_id].updated = 1;
> > }
> >
> > @@ -499,6 +517,10 @@ void rte_timer_manage(void)
> > uint64_t cur_time;
> > int i, ret;
> >
> > + /* timer manager only runs on EAL thread */
> > + if (lcore_id >= RTE_MAX_LCORE)
> > + return;
> > +
>
> Maybe an assert is more visible here. Else, if someone calls
> rte_timer_manage() from a non-EAL core, it will just exit
> silently.
>
> Maybe adding a comment in rte_timer.h saying that this function
> must be called from an EAL core would also help.
[LCM] accept.
>
>
>
> Regards,
> Olivier
