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authorMike Christie <michael.christie@oracle.com>2023-09-27 21:09:05 -0500
committerMartin K. Petersen <martin.petersen@oracle.com>2023-10-13 15:53:58 -0400
commite2f4ea40138e16d1dfd768f2dead8f3f75a85673 (patch)
tree81462ae049d9d29cf8fac79e2468b21126695b59 /include/target
parent428926796e7f3b2eb57b1d4886334d2f5abb35fa (diff)
scsi: target: Allow userspace to request direct submissions
This allows userspace to request the fabric drivers do direct submissions if they support it. With the new device file, submit_type, users can write 0 - 2 to control how commands are submitted to the backend: 0 - TARGET_FABRIC_DEFAULT_SUBMIT - LIO will use the fabric's default submission type. This is the default for compat. 1 - TARGET_DIRECT_SUBMIT - LIO will submit the cmd to the backend from the calling context if the fabric the cmd was received on supports it, else it will use the fabric's default type. 2 - TARGET_QUEUE_SUBMIT - LIO will queue the cmd to the LIO submission workqueue which will pass it to the backend. When using an NVMe drive and vhost-scsi with direct submission we see around a 20% improvement in 4K I/Os: fio jobs 1 2 4 8 10 -------------------------------------------------- defer 94K 190K 394K 770K 890K direct 128K 252K 488K 950K - And when using the queueing mode, we now no longer see issues like where the iSCSI tx thread is blocked in the block layer waiting on a tag so it can't respond to a nop or perform I/Os for other LUs. Signed-off-by: Mike Christie <michael.christie@oracle.com> Link: https://lore.kernel.org/r/20230928020907.5730-6-michael.christie@oracle.com Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
Diffstat (limited to 'include/target')
-rw-r--r--include/target/target_core_base.h1
1 files changed, 1 insertions, 0 deletions
diff --git a/include/target/target_core_base.h b/include/target/target_core_base.h
index 401abdf8a9ef..97099a5e3f6c 100644
--- a/include/target/target_core_base.h
+++ b/include/target/target_core_base.h
@@ -726,6 +726,7 @@ struct se_dev_attrib {
u32 unmap_granularity;
u32 unmap_granularity_alignment;
u32 max_write_same_len;
+ u8 submit_type;
struct se_device *da_dev;
struct config_group da_group;
};