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author | Bart Van Assche <bart.vanassche@wdc.com> | 2017-10-11 10:27:25 -0700 |
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committer | Doug Ledford <dledford@redhat.com> | 2017-10-18 10:49:54 -0400 |
commit | dea262094cdf629a3380061722b205de04057799 (patch) | |
tree | e22178edb4c32a45bb1e80b00fe6948014a8d597 /drivers/infiniband/ulp/srp | |
parent | IB/srpt: Cache global L_Key (diff) | |
download | linux-dev-dea262094cdf629a3380061722b205de04057799.tar.xz linux-dev-dea262094cdf629a3380061722b205de04057799.zip |
IB/srpt: Change default behavior from using SRQ to using RC
Although in the RC mode more resources are needed that mode has three
advantages over SRQ:
- It works with all RDMA adapters, even those that do not support
SRQ.
- Posting WRs and polling WCs does not trigger lock contention
because only one thread at a time accesses a WR or WC queue in
non-SRQ mode.
- The end-to-end flow control mechanism is used.
>From the IB spec:
C9-150.2.1: For QPs that are not associated with an SRQ, each HCA
receive queue shall generate end-to-end flow control credits. If
a QP is associated with an SRQ, the HCA receive queue shall not
generate end-to-end flow control credits.
Add new configfs attributes that allow to configure which mode to use
(/sys/kernel/config/target/srpt/$GUID/$GUID/attrib/use_srq). Note:
only the attribute for port 1 is relevant on multi-port adapters.
Signed-off-by: Bart Van Assche <bart.vanassche@wdc.com>
Signed-off-by: Doug Ledford <dledford@redhat.com>
Diffstat (limited to 'drivers/infiniband/ulp/srp')
0 files changed, 0 insertions, 0 deletions