Commit d49c9274 authored by paul luse's avatar paul luse Committed by Tomasz Zawadzki
Browse files

doc/accel: add section on opcode and engine overrides 



Signed-off-by: default avatarpaul luse <paul.e.luse@intel.com>
Change-Id: I70d5d544f213f30018cce6d5ce316aafa5ed3925
Reviewed-on: https://review.spdk.io/gerrit/c/spdk/spdk/+/12873


Tested-by: default avatarSPDK CI Jenkins <sys_sgci@intel.com>
Reviewed-by: default avatarBen Walker <benjamin.walker@intel.com>
Reviewed-by: default avatarAleksey Marchuk <alexeymar@nvidia.com>
parent efa33b85

doc/accel_fw.md

+32 −0
Original line number Diff line number Diff line
@@ -136,3 +136,35 @@ The software module is enabled by default. If no hardware engine is explicitly 
enabled via startup RPC as discussed earlier, the software module will use ISA-L

if available for functions such as CRC32C. Otherwise, standard glibc calls are

used to back the framework API.



### Engine to Operation Code Assignment {#accel_assignments}



When multiple engines are initialized, the accel framework will assign op codes to

engines by first assigning all op codes to the Software Engine and then overriding

op code assignments to Hardware Engines in the order in which they were initialized.

The RPC `accel_get_opc_assignments` can be used at any time to see the current

assignment map including the names of valid operations.  The RPC `accel_assign_opc`

can be used after initializing the desired Hardware Engines but before starting the

framework in the event that a specific override is desired.  Note that to start an

application and send startup RPC's use the `--wait-for-rpc` parameter and then use the

`framework_start_init` RPC to continue. For example, assume the DSA Engine is initialized

but for some reason the desire is to have the Software Module handle copies instead.

The following RPCs would accomplish the copy override:



`./scripts/rpc.py dsa_scan_accel_engine

./scripts/rpc.py accel_assign_opc -o copy -e software

./scripts/rpc.py framework_start_init

./scripts/rpc.py accel_get_opc_assignments

{

  "copy": "software",

  "fill": "dsa",

  "dualcast": "dsa",

  "compare": "dsa",

  "crc32c": "dsa",

  "copy_crc32c": "dsa",

  "compress": "software",

  "decompress": "software"

}`



To detemine the name of available engines and their supported operations use the

RPC `accel_get_engine_info`.