scsi: hisi_sas: Default enable interrupt coalescing

driver inclusion
category: bugfix
bugzilla: https://gitee.com/openeuler/kernel/issues/I9BBFQ
CVE: NA

----------------------------------------------------------------------

In the current interrupt reporting mode, each CQ entry reports an
interrupt. However, when there are a large number of I/O completion
interrupts, the following issue may occur:

[ 4682.678657][  C129] irq 134: nobody cared (try booting with the "irqpoll" option)
[ 4682.686137][  C129] CPU: 129 PID: 2567 Comm: irq/134-hisi_sa Kdump: loaded Tainted: G           OE     5.10.0 #1
[ 4682.696297][  C129] Hardware name: To be filled by O.E.M. KpxxxEVB 2P2T2N TB/To be filled by O.E.M., BIOS KpxxxEVB 2P2T2N TB 03/23/2023
[ 4682.708455][  C129] Call trace:
[ 4682.711589][  C129]  dump_backtrace+0x0/0x1e4
[ 4682.715934][  C129]  show_stack+0x20/0x2c
[ 4682.719933][  C129]  dump_stack+0xd8/0x140
[ 4682.724017][  C129]  __report_bad_irq+0x54/0x180
[ 4682.728625][  C129]  note_interrupt+0x1ec/0x2f0
[ 4682.733143][  C129]  handle_irq_event+0x118/0x1ac
[ 4682.737834][  C129]  handle_fasteoi_irq+0xc8/0x200
[ 4682.742613][  C129]  __handle_domain_irq+0x84/0xf0
[ 4682.747391][  C129]  gic_handle_irq+0x88/0x2c0
[ 4682.751822][  C129]  el1_irq+0xbc/0x140
[ 4682.755648][  C129]  _find_next_bit.constprop.0+0x20/0x94
[ 4682.761036][  C129]  cpumask_next+0x24/0x30
[ 4682.765208][  C129]  gic_ipi_send_mask+0x48/0x170
[ 4682.769900][  C129]  __ipi_send_mask+0x34/0x110
[ 4682.775720][  C129]  smp_cross_call+0x3c/0xcc
[ 4682.780064][  C129]  arch_send_call_function_single_ipi+0x38/0x44
[ 4682.786146][  C129]  send_call_function_single_ipi+0xd0/0xe0
[ 4682.791794][  C129]  generic_exec_single+0xb4/0x170
[ 4682.796659][  C129]  smp_call_function_single_async+0x2c/0x40
[ 4682.802395][  C129]  blk_mq_complete_request_remote.part.0+0xec/0x100
[ 4682.808822][  C129]  blk_mq_complete_request+0x30/0x70
[ 4682.813950][  C129]  scsi_mq_done+0x48/0xac
[ 4682.818128][  C129]  sas_scsi_task_done+0xb0/0x150 [libsas]
[ 4682.823692][  C129]  slot_complete_v3_hw+0x230/0x710 [hisi_sas_v3_hw]
[ 4682.830120][  C129]  cq_thread_v3_hw+0xbc/0x190 [hisi_sas_v3_hw]
[ 4682.836114][  C129]  irq_thread_fn+0x34/0xa4
[ 4682.840371][  C129]  irq_thread+0xc4/0x130
[ 4682.844455][  C129]  kthread+0x108/0x13c
[ 4682.848365][  C129]  ret_from_fork+0x10/0x18
[ 4682.852621][  C129] handlers:
[ 4682.855577][  C129] [<00000000949e52bf>] cq_interrupt_v3_hw [hisi_sas_v3_hw] threaded [<000000005d8e3b68>] cq_thread_v3_hw [hisi_sas_v3_hw]
[ 4682.868084][  C129] Disabling IRQ #134

When the IRQ management layer processes each hardware interrupt, if the
return value of the interrupt handler is IRQ_WAKE_THREAD, it will wake up
the handler thread for this interrupt action and set IRQTF_RUNTHREAD flag,
wait for the interrupt handling thread to clear the IRQTF_RUNTHREAD flag
after execution. Later in note_interrupt(), use irq_count to count
hardware interrupts and irqs_unhandled to count interrupts for which no
thread handler is responsible. When irq_count reaches 100000 and
irqs_unhandled reaches 99000, irq will be disabled.

In the performance test scenario, I/O completion hardware interrupts are
continuously and quickly generated. As a result, the interrupt processing
thread is cyclically called in irq_thread() and does not exit, this
affects the response of the interrupt thread to the hardware interrupt.
Finally, the irq is disabled.

Therefore, default enable interrupt coalescing to reduce the generation of
hardware interrupts, this helps interrupt processing threads to stop
calling in irq_thread().

For interrupt coalescing, the count of CQ entries is set to 10, and the
interrupt coalescing timeout period is set to 10us.

After interrupt coalescing is enabled by default, for fio with 4K read 32
iodepth scenario, the performance is improved by about 4% (1342k -> 1396k).

Signed-off-by: Yihang Li <liyihang9@huawei.com>
Signed-off-by: Bing Xia <xiabing12@h-partners.com>
(cherry picked from commit 7c1d68136323fff20caeae4ba4b6af15820b6799)

1 files changed, 5 insertions, 7 deletions

diff --git a/drivers/scsi/hisi_sas/hisi_sas_v3_hw.c b/drivers/scsi/hisi_sas/hisi_sas_v3_hw.c
index e714ea328e55ef..0551eb620d5555 100644
--- a/drivers/scsi/hisi_sas/hisi_sas_v3_hw.c
+++ b/drivers/scsi/hisi_sas/hisi_sas_v3_hw.c
@@ -631,9 +631,9 @@ static void init_reg_v3_hw(struct hisi_hba *hisi_hba)
 	hisi_sas_write32(hisi_hba, TRANS_LOCK_ICT_TIME, 0x4A817C80);
 	hisi_sas_write32(hisi_hba, HGC_SAS_TXFAIL_RETRY_CTRL, 0x108);
 	hisi_sas_write32(hisi_hba, CFG_AGING_TIME, 0x1);
-	hisi_sas_write32(hisi_hba, INT_COAL_EN, 0x1);
-	hisi_sas_write32(hisi_hba, OQ_INT_COAL_TIME, 0x1);
-	hisi_sas_write32(hisi_hba, OQ_INT_COAL_CNT, 0x1);
+	hisi_sas_write32(hisi_hba, INT_COAL_EN, 0x3);
+	hisi_sas_write32(hisi_hba, OQ_INT_COAL_TIME, 0xa);
+	hisi_sas_write32(hisi_hba, OQ_INT_COAL_CNT, 0xa);
 	hisi_sas_write32(hisi_hba, CQ_INT_CONVERGE_EN,
 			 hisi_sas_intr_conv);
 	hisi_sas_write32(hisi_hba, OQ_INT_SRC, 0xffff);
@@ -2761,11 +2761,9 @@ static void config_intr_coal_v3_hw(struct hisi_hba *hisi_hba)
 
 	if (hisi_hba->intr_coal_ticks == 0 ||
 	    hisi_hba->intr_coal_count == 0) {
-		hisi_sas_write32(hisi_hba, INT_COAL_EN, 0x1);
-		hisi_sas_write32(hisi_hba, OQ_INT_COAL_TIME, 0x1);
-		hisi_sas_write32(hisi_hba, OQ_INT_COAL_CNT, 0x1);
+		hisi_sas_write32(hisi_hba, OQ_INT_COAL_TIME, 0xa);
+		hisi_sas_write32(hisi_hba, OQ_INT_COAL_CNT, 0xa);
 	} else {
-		hisi_sas_write32(hisi_hba, INT_COAL_EN, 0x3);
 		hisi_sas_write32(hisi_hba, OQ_INT_COAL_TIME,
 				 hisi_hba->intr_coal_ticks);
 		hisi_sas_write32(hisi_hba, OQ_INT_COAL_CNT,