On Tue, Dec 13, 2011 at 09:49:52AM -0700, Steven Dake wrote:
> On 12/13/2011 07:11 AM, Angus Salkeld wrote:
> > To allow async cpg messages of 1M we need to:
> > 1) increase the totem queue size by 4
>
> multiple of 4
>
> > 2) align the critical level to one large message free
> >
>
> Add following to commit message unless you disagree:
>
> Kind of hacky. Don't particularly like that the max message queue is
> 4MB instead of 1MB.
>
> Does this mean that 1MB will never be used in the buffer because of
> TOTEM_Q_LEVEL_CRITICAL?
>
There are a number of reasons for doing this:
1)
We can't let cpg_mcast_joined() fail because the user will not see it
and will assume is has succeded.
2)
The reason I am getting good performance is by providing a negitive
feedback loop from the totem q and the IPC/poll system. This relies
on 4 q states low/med/high/crit. With messages of size 1M you
now have a q of size one and now go from level low to crit instantly
then back to low as messages are put on and taken off. I don't think
this is the best behaviour. By having a q size of 4 allows the system
to utilize the q better and give us time to respond to changes in
the q level.
3)
To effective achieve flow control with a q of size 1 would require
all the clients to request the space on the q like is done in
totempg_groups_joined_reserve() but probably in shared memory
This would take quite a bit of re-work.
> Reviewed-by: Steven Dake <sdake@xxxxxxxxxx>
>
> Regards
> -steve
>
> > Signed-off-by: Angus Salkeld <asalkeld@xxxxxxxxxx>
> > ---
> > exec/totempg.c | 13 +++++++++----
> > include/corosync/engine/coroapi.h | 6 ++++--
> > include/corosync/totem/totem.h | 2 +-
> > 3 files changed, 14 insertions(+), 7 deletions(-)
> >
> > diff --git a/exec/totempg.c b/exec/totempg.c
> > index 3ece489..924979c 100644
> > --- a/exec/totempg.c
> > +++ b/exec/totempg.c
> > @@ -1185,6 +1185,11 @@ int totempg_groups_mcast_joined (
> > return (res);
> > }
> >
> > +#ifndef HAVE_SMALL_MEMORY_FOOTPRINT
> > +#undef MESSAGE_QUEUE_MAX
> > +#define MESSAGE_QUEUE_MAX ((4 * MESSAGE_SIZE_MAX) / totempg_totem_config->net_mtu)
> > +#endif /* HAVE_SMALL_MEMORY_FOOTPRINT */
> > +
> > static void check_q_level(
> > void *totempg_groups_instance)
> > {
> > @@ -1193,15 +1198,15 @@ static void check_q_level(
> > struct totempg_group_instance *instance = (struct totempg_group_instance *)totempg_groups_instance;
> >
> > old_level = instance->q_level;
> > - percent_used = 100 - (totemmrp_avail () * 100 / 800); /*(1024*1024/1500)*/
> > + percent_used = 100 - ((totemmrp_avail () * 100) / MESSAGE_QUEUE_MAX);
> >
> > - if (percent_used > 90 && instance->q_level != TOTEM_Q_LEVEL_CRITICAL) {
> > + if (percent_used >= 75 && instance->q_level != TOTEM_Q_LEVEL_CRITICAL) {
> > instance->q_level = TOTEM_Q_LEVEL_CRITICAL;
> > } else if (percent_used < 30 && instance->q_level != TOTEM_Q_LEVEL_LOW) {
> > instance->q_level = TOTEM_Q_LEVEL_LOW;
> > - } else if (percent_used > 40 && percent_used < 60 && instance->q_level != TOTEM_Q_LEVEL_GOOD) {
> > + } else if (percent_used > 40 && percent_used < 50 && instance->q_level != TOTEM_Q_LEVEL_GOOD) {
> > instance->q_level = TOTEM_Q_LEVEL_GOOD;
> > - } else if (percent_used > 70 && percent_used < 80 && instance->q_level != TOTEM_Q_LEVEL_HIGH) {
> > + } else if (percent_used > 60 && percent_used < 70 && instance->q_level != TOTEM_Q_LEVEL_HIGH) {
> > instance->q_level = TOTEM_Q_LEVEL_HIGH;
> > }
> > if (totem_queue_level_changed && old_level != instance->q_level) {
> > diff --git a/include/corosync/engine/coroapi.h b/include/corosync/engine/coroapi.h
> > index 567d14f..cabcbb3 100644
> > --- a/include/corosync/engine/coroapi.h
> > +++ b/include/corosync/engine/coroapi.h
> > @@ -72,15 +72,17 @@ struct corosync_tpg_group {
> >
> > #define INTERFACE_MAX 2
> >
> > +#ifndef MESSAGE_QUEUE_MAX
> > #ifdef HAVE_SMALL_MEMORY_FOOTPRINT
> > #define PROCESSOR_COUNT_MAX 16
> > #define MESSAGE_SIZE_MAX 1024*64
> > #define MESSAGE_QUEUE_MAX 512
> > #else
> > #define PROCESSOR_COUNT_MAX 384
> > -#define MESSAGE_SIZE_MAX 1024*1024 /* (1MB) */
> > -#define MESSAGE_QUEUE_MAX MESSAGE_SIZE_MAX / totem_config->net_mtu
> > +#define MESSAGE_SIZE_MAX 1024*1024
> > +#define MESSAGE_QUEUE_MAX ((4 * MESSAGE_SIZE_MAX) / totem_config->net_mtu)
> > #endif /* HAVE_SMALL_MEMORY_FOOTPRINT */
> > +#endif /* MESSAGE_QUEUE_MAX */
> >
> > #define TOTEM_AGREED 0
> > #define TOTEM_SAFE 1
> > diff --git a/include/corosync/totem/totem.h b/include/corosync/totem/totem.h
> > index 2166143..3d00318 100644
> > --- a/include/corosync/totem/totem.h
> > +++ b/include/corosync/totem/totem.h
> > @@ -44,7 +44,7 @@
> > #else
> > #define PROCESSOR_COUNT_MAX 384
> > #define MESSAGE_SIZE_MAX 1024*1024 /* (1MB) */
> > -#define MESSAGE_QUEUE_MAX MESSAGE_SIZE_MAX / totem_config->net_mtu
> > +#define MESSAGE_QUEUE_MAX ((4 * MESSAGE_SIZE_MAX) / totem_config->net_mtu)
> > #endif /* HAVE_SMALL_MEMORY_FOOTPRINT */
> >
> > #define FRAME_SIZE_MAX 10000
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