From 4959e61b83a3bc53d49b023dcb4dc50150c2795e Mon Sep 17 00:00:00 2001 From: Shivasharan S Date: Fri, 5 Jan 2018 05:27:45 -0800 Subject: scsi: megaraid_sas: Selectively apply stream detection based on IO type Performance improvement: Current driver calls stream detection unconditionally for all IOs. Stream Detection logic is not required for most of the fast path IO. To improve performance, avoid stream detection logic and do it only if required. Below are the cases where stream detection is required in driver: 1. All non-FastPath IOs (IOs going to FW) 2. Fast Path reads sent to ReadAhead capable VDs. Signed-off-by: Sumit Saxena Signed-off-by: Shivasharan S Signed-off-by: Martin K. Petersen --- drivers/scsi/megaraid/megaraid_sas_fusion.c | 24 ++++++++++++++---------- 1 file changed, 14 insertions(+), 10 deletions(-) diff --git a/drivers/scsi/megaraid/megaraid_sas_fusion.c b/drivers/scsi/megaraid/megaraid_sas_fusion.c index 74dadd052be4..ef36f2ac7cb6 100644 --- a/drivers/scsi/megaraid/megaraid_sas_fusion.c +++ b/drivers/scsi/megaraid/megaraid_sas_fusion.c @@ -2664,16 +2664,6 @@ megasas_build_ldio_fusion(struct megasas_instance *instance, praid_context = &io_request->RaidContext; if (instance->adapter_type == VENTURA_SERIES) { - spin_lock_irqsave(&instance->stream_lock, spinlock_flags); - megasas_stream_detect(instance, cmd, &io_info); - spin_unlock_irqrestore(&instance->stream_lock, spinlock_flags); - /* In ventura if stream detected for a read and it is read ahead - * capable make this IO as LDIO - */ - if (is_stream_detected(&io_request->RaidContext.raid_context_g35) && - io_info.isRead && io_info.ra_capable) - fp_possible = false; - /* FP for Optimal raid level 1. * All large RAID-1 writes (> 32 KiB, both WT and WB modes) * are built by the driver as LD I/Os. @@ -2699,6 +2689,20 @@ megasas_build_ldio_fusion(struct megasas_instance *instance, } } + if (!fp_possible || + (io_info.isRead && io_info.ra_capable)) { + spin_lock_irqsave(&instance->stream_lock, + spinlock_flags); + megasas_stream_detect(instance, cmd, &io_info); + spin_unlock_irqrestore(&instance->stream_lock, + spinlock_flags); + /* In ventura if stream detected for a read and it is + * read ahead capable make this IO as LDIO + */ + if (is_stream_detected(&io_request->RaidContext.raid_context_g35)) + fp_possible = false; + } + /* If raid is NULL, set CPU affinity to default CPU0 */ if (raid) megasas_set_raidflag_cpu_affinity(praid_context, -- cgit v1.2.3