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| author | Chuck Lever <chuck.lever@oracle.com> | 2019-10-17 20:31:53 +0200 |
|---|---|---|
| committer | Anna Schumaker <Anna.Schumaker@Netapp.com> | 2019-10-24 16:30:40 +0200 |
| commit | 614f3c96d7e5efd1c4dc699524857130a52c6a7f (patch) | |
| tree | 05b6a845cd5731657b7f63c5af28a597b2bedd38 /include | |
| parent | xprtrdma: Refactor rpcrdma_prepare_msg_sges() (diff) | |
| download | linux-614f3c96d7e5efd1c4dc699524857130a52c6a7f.tar.xz linux-614f3c96d7e5efd1c4dc699524857130a52c6a7f.zip | |
xprtrdma: Pull up sometimes
On some platforms, DMA mapping part of a page is more costly than
copying bytes. Restore the pull-up code and use that when we
think it's going to be faster. The heuristic for now is to pull-up
when the size of the RPC message body fits in the buffer underlying
the head iovec.
Indeed, not involving the I/O MMU can help the RPC/RDMA transport
scale better for tiny I/Os across more RDMA devices. This is because
interaction with the I/O MMU is eliminated, as is handling a Send
completion, for each of these small I/Os. Without the explicit
unmapping, the NIC no longer needs to do a costly internal TLB shoot
down for buffers that are just a handful of bytes.
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
Diffstat (limited to 'include')
| -rw-r--r-- | include/trace/events/rpcrdma.h | 4 |
1 files changed, 4 insertions, 0 deletions
diff --git a/include/trace/events/rpcrdma.h b/include/trace/events/rpcrdma.h index f8edab91e09c..213c72585a5f 100644 --- a/include/trace/events/rpcrdma.h +++ b/include/trace/events/rpcrdma.h @@ -532,6 +532,8 @@ DEFINE_WRCH_EVENT(write); DEFINE_WRCH_EVENT(reply); TRACE_DEFINE_ENUM(rpcrdma_noch); +TRACE_DEFINE_ENUM(rpcrdma_noch_pullup); +TRACE_DEFINE_ENUM(rpcrdma_noch_mapped); TRACE_DEFINE_ENUM(rpcrdma_readch); TRACE_DEFINE_ENUM(rpcrdma_areadch); TRACE_DEFINE_ENUM(rpcrdma_writech); @@ -540,6 +542,8 @@ TRACE_DEFINE_ENUM(rpcrdma_replych); #define xprtrdma_show_chunktype(x) \ __print_symbolic(x, \ { rpcrdma_noch, "inline" }, \ + { rpcrdma_noch_pullup, "pullup" }, \ + { rpcrdma_noch_mapped, "mapped" }, \ { rpcrdma_readch, "read list" }, \ { rpcrdma_areadch, "*read list" }, \ { rpcrdma_writech, "write list" }, \ |