diff options
Diffstat (limited to 'Documentation/block/null_blk.txt')
| -rw-r--r-- | Documentation/block/null_blk.txt | 20 |
1 files changed, 10 insertions, 10 deletions
diff --git a/Documentation/block/null_blk.txt b/Documentation/block/null_blk.txt index 9e1b047fd13d..5603dad5534b 100644 --- a/Documentation/block/null_blk.txt +++ b/Documentation/block/null_blk.txt @@ -18,7 +18,7 @@ The following instances are possible: - Bio-based. IO requests are submitted directly to the device driver. - Directly accepts bio data structure and returns them. -All of them has a completion queue for each core in the system. +All of them have a completion queue for each core in the system. II. Module parameters applicable for all instances: @@ -30,7 +30,7 @@ queue_mode=[0-2]: Default: 2-Multi-queue 2: Multi-queue. home_node=[0--nr_nodes]: Default: NUMA_NO_NODE - Selects what socket the data structures is allocated from. + Selects what CPU node the data structures are allocated from. gb=[Size in GB]: Default: 250GB The size of the device reported to the system. @@ -38,34 +38,34 @@ gb=[Size in GB]: Default: 250GB bs=[Block size (in bytes)]: Default: 512 bytes The block size reported to the system. -nr_devices=[Num. devices]: Default: 2 +nr_devices=[Number of devices]: Default: 2 Number of block devices instantiated. They are instantiated as /dev/nullb0, etc. -irq_mode=[0-2]: Default: Soft-irq +irq_mode=[0-2]: Default: 1-Soft-irq The completion mode used for completing IOs to the block-layer. 0: None. - 1: Soft-irq. Uses ipi to complete IOs across sockets. Simulates the overhead - when IOs are issued from another socket than the home the device is + 1: Soft-irq. Uses IPI to complete IOs across CPU nodes. Simulates the overhead + when IOs are issued from another CPU node than the home the device is connected to. 2: Timer: Waits a specific period (completion_nsec) for each IO before completion. -completion_nsec=[Num. ns]: Default: 10.000ns +completion_nsec=[ns]: Default: 10.000ns Combined with irq_mode=2 (timer). The time each completion event must wait. submit_queues=[0..nr_cpus]: The number of submission queues attached to the device driver. If unset, it defaults to 1 on single-queue and bio-based instances. For multi-queue, - its ignored when use_per_node_hctx module parameter is 1. + it is ignored when use_per_node_hctx module parameter is 1. -hw_queue_depth=[0..qdepth]: Defaults: 64 +hw_queue_depth=[0..qdepth]: Default: 64 The hardware queue depth of the device. III: Multi-queue specific parameters -use_per_node_hctx=[0/1]: Defaults: 1 +use_per_node_hctx=[0/1]: Default: 1 If 1, the multi-queue block layer is instantiated with a hardware dispatch queue for each CPU node in the system. If 0, it is instantiated with the number of queues defined in the submit_queues parameter. |