t/io_uring: Reporting bandwidth

When performing tests at various block size, it's sometimes a bit
difficult to estimate if we reach the limit of the datapath.

This commit offer to simply prints the resulting bandwitdh of the IOPS
multiplied by the block size.

A typical output looks like :

  [user@hosŧ] t/io_uring -b512 -d128 -c32 -s32 -p1 -F1 -B1 -n4 /dev/nvme0n1
   ...
   IOPS=729856, BW=356 MiB/s, IOS/call=32/32, inflight=(105 119 108 109)

  [user@host] t/io_uring -b4096 -d128 -c32 -s32 -p1 -F1 -B1 -n4 /dev/nvme0n1
   ...
   IOPS=746368, BW=2915 MiB/s, IOS/call=32/31, inflight=(121 115 122 122)

In the 4K case, as for a PCI Gen3 product, we are clearly limited by the
bandwidth while in the 512 case we hit latency issues.

BW is expressed in MiB/sec.

Signed-off-by: Erwan Velu <e.velu@criteo.com>

diff --git a/t/io_uring.c b/t/io_uring.c
index 0acbf0b402b3602b63bf429de8c194093f0a0ea0..cf59fe37dee770285e0975d0949cc63e45d62ba5 100644 (file)
--- a/t/io_uring.c
+++ b/t/io_uring.c
@@ -727,6 +727,7 @@ int main(int argc, char *argv[])
                unsigned long this_reap = 0;
                unsigned long this_call = 0;
                unsigned long rpc = 0, ipc = 0;
+               unsigned long iops;
 
                sleep(1);
                for (j = 0; j < nthreads; j++) {
@@ -740,8 +741,9 @@ int main(int argc, char *argv[])
                } else
                        rpc = ipc = -1;
                file_depths(fdepths);
-               printf("IOPS=%lu, IOS/call=%ld/%ld, inflight=(%s)\n",
-                               this_done - done, rpc, ipc, fdepths);
+               iops = this_done - done;
+               printf("IOPS=%lu, BW=%luMiB/s, IOS/call=%ld/%ld, inflight=(%s)\n",
+                               iops, iops * (1048576 / bs), rpc, ipc, fdepths);
                done = this_done;
                calls = this_call;
                reap = this_reap;