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From: <Olaf.Krzikalla@dlr.de>
To: <linux-rdma@vger.kernel.org>
Subject: Understanding the allocation size of mlx5_alloc_buf
Date: Thu, 6 Jul 2023 12:48:46 +0000	[thread overview]
Message-ID: <7f6a9b854205410eb45a665b1e84c0f2@dlr.de> (raw)

Hi @all,

creating connections via create_qp fails on our cluster for rather small numbers of processes (128 is working, 256 not) due to an out-of-memory error. I've tracked down the issue to an mlx5_alloc_buf call, which allocates ~500kB per call, which seems to be a lot.

heaptrack tells me the following:

34.47M peak memory consumed over 92 calls from
mlx5_alloc_buf
  in /usr/lib64/libibverbs/libmlx5-rdmav34.so
8.65M consumed over 16 calls from:
    create_qp
      in /usr/lib64/libibverbs/libmlx5-rdmav34.so
    mlx5_create_qp
      in /usr/lib64/libibverbs/libmlx5-rdmav34.so
.

Can anyone help me to understand, what causes a 500kB allocation in create_qp? Maybe it is some sort of a configuration issue, which I can handle somehow.

Thanks for help and best regards
Olaf Krzikalla


System information:
CentOS Linux 7 (Core)
Linux 3.10.0-1160.88.1.el7.x86_64
CA 'mlx5_0'
        CA type: MT4123
        Number of ports: 1
        Firmware version: 20.33.1048
        Hardware version: 0







             reply	other threads:[~2023-07-06 12:49 UTC|newest]

Thread overview: 2+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2023-07-06 12:48 Olaf.Krzikalla [this message]
2023-07-06 16:47 ` Understanding the allocation size of mlx5_alloc_buf Leon Romanovsky

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