From f86d6f9c49f67b05d117495dc440aaa18c66a9da Mon Sep 17 00:00:00 2001 From: Michal Schmidt Date: Wed, 12 Apr 2023 10:19:27 +0200 Subject: [PATCH] ice: sleep, don't busy-wait, for ICE_CTL_Q_SQ_CMD_TIMEOUT MIME-Version: 1.0 Content-Type: text/plain; charset=utf8 Content-Transfer-Encoding: 8bit The driver polls for ice_sq_done() with a 100 µs period for up to 1 s and it uses udelay to do that. Let's use usleep_range instead. We know sleeping is allowed here, because we're holding a mutex (cq->sq_lock). To preserve the total max waiting time, measure the timeout in jiffies. ICE_CTL_Q_SQ_CMD_TIMEOUT is used also in ice_release_res(), but there the polling period is 1 ms (i.e. 10 times longer). Since the timeout was expressed in terms of the number of loops, the total timeout in this function is 10 s. I do not know if this is intentional. This patch keeps it. The patch lowers the CPU usage of the ice-gnss- kernel thread on my system from ~8 % to less than 1 %. I received a report of high CPU usage with ptp4l where the busy-waiting in ice_sq_send_cmd dominated the profile. This patch has been tested in that usecase too and it made a huge improvement there. Tested-by: Brent Rowsell Signed-off-by: Michal Schmidt Reviewed-by: Arkadiusz Kubalewski Reviewed-by: Simon Horman Tested-by: Sunitha Mekala (A Contingent worker at Intel) Signed-off-by: Tony Nguyen --- drivers/net/ethernet/intel/ice/ice_common.c | 14 +++++++------- drivers/net/ethernet/intel/ice/ice_controlq.c | 9 +++++---- drivers/net/ethernet/intel/ice/ice_controlq.h | 2 +- 3 files changed, 13 insertions(+), 12 deletions(-) diff --git a/drivers/net/ethernet/intel/ice/ice_common.c b/drivers/net/ethernet/intel/ice/ice_common.c index f4c256563248..3638598d732b 100644 --- a/drivers/net/ethernet/intel/ice/ice_common.c +++ b/drivers/net/ethernet/intel/ice/ice_common.c @@ -1992,19 +1992,19 @@ ice_acquire_res_exit: */ void ice_release_res(struct ice_hw *hw, enum ice_aq_res_ids res) { - u32 total_delay = 0; + unsigned long timeout; int status; - status = ice_aq_release_res(hw, res, 0, NULL); - /* there are some rare cases when trying to release the resource * results in an admin queue timeout, so handle them correctly */ - while ((status == -EIO) && (total_delay < ICE_CTL_Q_SQ_CMD_TIMEOUT)) { - mdelay(1); + timeout = jiffies + 10 * ICE_CTL_Q_SQ_CMD_TIMEOUT; + do { status = ice_aq_release_res(hw, res, 0, NULL); - total_delay++; - } + if (status != -EIO) + break; + usleep_range(1000, 2000); + } while (time_before(jiffies, timeout)); } /** diff --git a/drivers/net/ethernet/intel/ice/ice_controlq.c b/drivers/net/ethernet/intel/ice/ice_controlq.c index c8fb10106ec3..d2faf1baad2f 100644 --- a/drivers/net/ethernet/intel/ice/ice_controlq.c +++ b/drivers/net/ethernet/intel/ice/ice_controlq.c @@ -964,7 +964,7 @@ ice_sq_send_cmd(struct ice_hw *hw, struct ice_ctl_q_info *cq, struct ice_aq_desc *desc_on_ring; bool cmd_completed = false; struct ice_sq_cd *details; - u32 total_delay = 0; + unsigned long timeout; int status = 0; u16 retval = 0; u32 val = 0; @@ -1057,13 +1057,14 @@ ice_sq_send_cmd(struct ice_hw *hw, struct ice_ctl_q_info *cq, cq->sq.next_to_use = 0; wr32(hw, cq->sq.tail, cq->sq.next_to_use); + timeout = jiffies + ICE_CTL_Q_SQ_CMD_TIMEOUT; do { if (ice_sq_done(hw, cq)) break; - udelay(ICE_CTL_Q_SQ_CMD_USEC); - total_delay++; - } while (total_delay < ICE_CTL_Q_SQ_CMD_TIMEOUT); + usleep_range(ICE_CTL_Q_SQ_CMD_USEC, + ICE_CTL_Q_SQ_CMD_USEC * 3 / 2); + } while (time_before(jiffies, timeout)); /* if ready, copy the desc back to temp */ if (ice_sq_done(hw, cq)) { diff --git a/drivers/net/ethernet/intel/ice/ice_controlq.h b/drivers/net/ethernet/intel/ice/ice_controlq.h index e790b2f4e437..950b7f4a7a05 100644 --- a/drivers/net/ethernet/intel/ice/ice_controlq.h +++ b/drivers/net/ethernet/intel/ice/ice_controlq.h @@ -34,7 +34,7 @@ enum ice_ctl_q { }; /* Control Queue timeout settings - max delay 1s */ -#define ICE_CTL_Q_SQ_CMD_TIMEOUT 10000 /* Count 10000 times */ +#define ICE_CTL_Q_SQ_CMD_TIMEOUT HZ /* Wait max 1s */ #define ICE_CTL_Q_SQ_CMD_USEC 100 /* Check every 100usec */ #define ICE_CTL_Q_ADMIN_INIT_TIMEOUT 10 /* Count 10 times */ #define ICE_CTL_Q_ADMIN_INIT_MSEC 100 /* Check every 100msec */ -- 2.34.1