diff options
| author | Michael Brown <mcb30@ipxe.org> | 2021-01-31 23:29:45 +0000 |
|---|---|---|
| committer | Michael Brown <mcb30@ipxe.org> | 2021-01-31 23:29:45 +0000 |
| commit | def46cf344dc9981a0901a1293d4513efafe14d2 (patch) | |
| tree | 4957930e4abe8c053559ce3d2955b607d862dd3f | |
| parent | ba20ba42731b8b03a5db2f81f876fccd56257b0f (diff) | |
| download | qemu-ipxe-hermon_link_poll.tar.gz | |
[hermon] Limit link poll frequency in DOWN statehermon_link_poll
Some older versions of the hardware (and/or firmware) do not report an
event when an Infiniband link reaches the INIT state. The driver
works around this missing event by calling ib_smc_update() on each
event queue poll while the link is in the DOWN state.
Commit 6cb12ee ("[hermon] Increase polling rate for command
completions") addressed this by speeding up the time taken to issue
each command invoked by ib_smc_update(). Experimentation shows that
the impact is still significant: for example, in a situation where an
unplugged port is opened, the throughput on the other port can be
reduced by over 99%.
Fix by throttling the rate at which link polling is attempted.
Debugged-by: Christian Iversen <ci@iversenit.dk>
Signed-off-by: Michael Brown <mcb30@ipxe.org>
| -rw-r--r-- | src/drivers/infiniband/hermon.c | 9 | ||||
| -rw-r--r-- | src/drivers/infiniband/hermon.h | 9 |
2 files changed, 17 insertions, 1 deletions
diff --git a/src/drivers/infiniband/hermon.c b/src/drivers/infiniband/hermon.c index 2a9649de..50ba4f4e 100644 --- a/src/drivers/infiniband/hermon.c +++ b/src/drivers/infiniband/hermon.c @@ -2130,6 +2130,8 @@ static void hermon_poll_eq ( struct ib_device *ibdev ) { struct hermon_event_queue *hermon_eq = &hermon->eq; union hermonprm_event_entry *eqe; union hermonprm_doorbell_register db_reg; + unsigned long now; + unsigned long elapsed; unsigned int eqe_idx_mask; unsigned int event_type; @@ -2138,7 +2140,12 @@ static void hermon_poll_eq ( struct ib_device *ibdev ) { */ if ( ib_is_open ( ibdev ) && ( ibdev->port_state == IB_PORT_STATE_DOWN ) ) { - ib_smc_update ( ibdev, hermon_mad ); + now = currticks(); + elapsed = ( now - hermon->last_poll ); + if ( elapsed >= HERMON_LINK_POLL_INTERVAL ) { + hermon->last_poll = now; + ib_smc_update ( ibdev, hermon_mad ); + } } /* Poll event queue */ diff --git a/src/drivers/infiniband/hermon.h b/src/drivers/infiniband/hermon.h index 61f3b041..6d7471df 100644 --- a/src/drivers/infiniband/hermon.h +++ b/src/drivers/infiniband/hermon.h @@ -894,6 +894,8 @@ struct hermon { /** Event queue */ struct hermon_event_queue eq; + /** Last unsolicited link state poll */ + unsigned long last_poll; /** Unrestricted LKey * * Used to get unrestricted memory access. @@ -930,6 +932,13 @@ struct hermon { /** Memory key prefix */ #define HERMON_MKEY_PREFIX 0x77000000UL +/** Link poll interval + * + * Used when we need to poll for link state (rather than relying upon + * receiving an event). + */ +#define HERMON_LINK_POLL_INTERVAL ( TICKS_PER_SEC / 2 ) + /* * HCA commands * |