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| author | Mike Christie <michael.christie@oracle.com> | 2023-09-27 21:09:05 -0500 |
|---|---|---|
| committer | Martin K. Petersen <martin.petersen@oracle.com> | 2023-10-13 15:53:58 -0400 |
| commit | e2f4ea40138e16d1dfd768f2dead8f3f75a85673 (patch) | |
| tree | 81462ae049d9d29cf8fac79e2468b21126695b59 /include/target | |
| parent | 428926796e7f3b2eb57b1d4886334d2f5abb35fa (diff) | |
| download | linux-e2f4ea40138e16d1dfd768f2dead8f3f75a85673.tar.gz linux-e2f4ea40138e16d1dfd768f2dead8f3f75a85673.tar.bz2 linux-e2f4ea40138e16d1dfd768f2dead8f3f75a85673.zip | |
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.h | 1 |
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; }; |