| Message ID | 20240930201307.330692-5-mschmidt@redhat.com (mailing list archive) |
|---|---|
| State | New |
| Delegated to: | Netdev Maintainers |
| Headers | show |
| Series | qed: 'ethtool -d' faster, less latency | expand |
diff --git a/drivers/net/ethernet/qlogic/qed/qed_hw.c b/drivers/net/ethernet/qlogic/qed/qed_hw.c index 6263f847b6b9..9e5f0dbc8a07 100644 --- a/drivers/net/ethernet/qlogic/qed/qed_hw.c +++ b/drivers/net/ethernet/qlogic/qed/qed_hw.c @@ -596,6 +596,7 @@ static int qed_dmae_operation_wait(struct qed_hwfn *p_hwfn) barrier(); while (*p_hwfn->dmae_info.p_completion_word != DMAE_COMPLETION_VAL) { udelay(DMAE_MIN_WAIT_TIME); + cond_resched(); if (++wait_cnt > wait_cnt_limit) { DP_NOTICE(p_hwfn->cdev, "Timed-out waiting for operation to complete. Completion word is 0x%08x expected 0x%08x.\n",
It is OK to sleep in qed_dmae_operation_wait, because it is called only in process context, while holding p_hwfn->dmae_info.mutex from one of the qed_dmae_{host,grc}2{host,grc} functions. The udelay(DMAE_MIN_WAIT_TIME=2) in the function is too short to replace with usleep_range, but at least it's a suitable point for checking if we should give up the CPU with cond_resched(). This lowers the latency caused by 'ethtool -d' from 10 ms to less than 2 ms on my test system with voluntary preemption. Signed-off-by: Michal Schmidt <mschmidt@redhat.com> --- drivers/net/ethernet/qlogic/qed/qed_hw.c | 1 + 1 file changed, 1 insertion(+)