On Wed, Apr 17, 2013 at 10:36 PM, Yan Burman <yanb@xxxxxxxxxxxx> wrote: > Hi. > > I've been trying to do some benchmarks for NFS over RDMA and I seem to only get about half of the bandwidth that the HW can give me. > My setup consists of 2 servers each with 16 cores, 32Gb of memory, and Mellanox ConnectX3 QDR card over PCI-e gen3. > These servers are connected to a QDR IB switch. The backing storage on the server is tmpfs mounted with noatime. > I am running kernel 3.5.7. > > When running ib_send_bw, I get 4.3-4.5 GB/sec for block sizes 4-512K. > When I run fio over rdma mounted nfs, I get 260-2200MB/sec for the same block sizes (4-512K). running over IPoIB-CM, I get 200-980MB/sec. > I got to these results after the following optimizations: > 1. Setting IRQ affinity to the CPUs that are part of the NUMA node the card is on > 2. Increasing /proc/sys/sunrpc/svc_rdma/max_outbound_read_requests and /proc/sys/sunrpc/svc_rdma/max_requests to 256 on server > 3. Increasing RPCNFSDCOUNT to 32 on server Did you try to affine nfsd to corresponding CPUs where your IB card locates? Given that you see a bottleneck on CPU (as in your later email), it might be worth trying. > 4. FIO arguments: --rw=randread --bs=4k --numjobs=2 --iodepth=128 --ioengine=libaio --size=100000k --prioclass=1 --prio=0 --cpumask=255 --loops=25 --direct=1 --invalidate=1 --fsync_on_close=1 --randrepeat=1 --norandommap --group_reporting --exitall --buffered=0 > On client side, it may be good to affine FIO processes and nfsiod to CPUs where IB card locates as well, in case client is the bottleneck. -- Thanks, Tao -- To unsubscribe from this list: send the line "unsubscribe linux-nfs" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
