https://bugzilla.kernel.org/show_bug.cgi?id=109391
Bug ID: 109391
Summary: Packet and byte counters only 32bit
Product: Drivers
Version: 2.5
Kernel Version: git HEAD
Hardware: All
OS: Linux
Tree: Mainline
Status: NEW
Severity: normal
Priority: P1
Component: Infiniband/RDMA
Assignee: [email protected]
Reporter: [email protected]
Regression: No
Trying to find packet and byte counters for the RDMA transports I stumbled upon
this directory:
/sys/class/infiniband/mlx5_1/ports/1/counters/
This seems to have all the requested data; but, looking again, I can see
port_rcv_data: 4294967295
which looks awful.
And indeed, in
https://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/tree/drivers/infiniband/core/sysfs.c#n401
there's a 32bit width, with explicit code in
https://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/tree/drivers/infiniband/hw/qib/qib_mad.c#n1507
to cap on that limit...
That is useless for the upcoming speeds. The MLX5 driver can drive Connect-X4
cards which go 100GBit/sec; that is 11GByte/sec, which means that the 32bit
counter will overflow ~3 times a second. So it can't be monitored.
Please provide 64bit counters (for packets and bytes, at least)!
Thanks a lot.
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