1. 13 Jan, 2015 35 commits
  2. 12 Jan, 2015 5 commits
    • David S. Miller's avatar
      Merge branch 'tuntap_queues' · d2c60b13
      David S. Miller authored
      Pankaj Gupta says:
      
      ====================
      Increase the limit of tuntap queues
      
      Networking under KVM works best if we allocate a per-vCPU rx and tx
      queue in a virtual NIC. This requires a per-vCPU queue on the host side.
      Modern physical NICs have multiqueue support for large number of queues.
      To scale vNIC to run multiple queues parallel to maximum number of vCPU's
      we need to increase number of queues support in tuntap.
      
      Changes from v4:
      PATCH2: Michael.S.Tsirkin - Updated change comment message.
      
      Changes from v3:
      PATCH1: Michael.S.Tsirkin - Some cleanups and updated commit message.
                                  Perf numbers on 10 Gbs NIC
      Changes from v2:
      PATCH 3: David Miller     - flex array adds extra level of indirection
                                  for preallocated array.(dropped, as flow array
      			    is allocated using kzalloc with failover to zalloc).
      Changes from v1:
      PATCH 2: David Miller     - sysctl changes to limit number of queues
                                  not required for unprivileged users(dropped).
      
      Changes from RFC
      PATCH 1: Sergei Shtylyov  - Add an empty line after declarations.
      PATCH 2: Jiri Pirko -       Do not introduce new module paramaters.
      	 Michael.S.Tsirkin- We can use sysctl for limiting max number
                                  of queues.
      
      This series is to increase the number of tuntap queues. Original work is being
      done by 'jasowang@redhat.com'. I am taking this 'https://lkml.org/lkml/2013/6/19/29'
      patch series as a reference. As per discussion in the patch series:
      
      There were two reasons which prevented us from increasing number of tun queues:
      
      - The netdev_queue array in netdevice were allocated through kmalloc, which may
        cause a high order memory allocation too when we have several queues.
        E.g. sizeof(netdev_queue) is 320, which means a high order allocation would
        happens when the device has more than 16 queues.
      
      - We store the hash buckets in tun_struct which results a very large size of
        tun_struct, this high order memory allocation fail easily when the memory is
        fragmented.
      
      The patch 60877a32
      
       increases the number of tx
      queues. Memory allocation fallback to vzalloc() when kmalloc() fails.
      
      This series tries to address following issues:
      
      - Increase the number of netdev_queue queues for rx similarly its done for tx
        queues by falling back to vzalloc() when memory allocation with kmalloc() fails.
      
      - Increase number of queues to 256, maximum number is equal to maximum number
        of vCPUS allowed in a guest.
      
      I have also done testing with multiple parallel Netperf sessions for different
      combination of queues and CPU's. It seems to be working fine without much increase
      in cpu load with increase in number of queues. I also see good increase in throughput
      with increase in number of queues. Though i had limitation of 8 physical CPU's.
      
      For this test: Two Hosts(Host1 & Host2) are directly connected with cable
      Host1 is running Guest1. Data is sent from Host2 to Guest1 via Host1.
      
      Host kernel: 3.19.0-rc2+, AMD Opteron(tm) Processor 6320
      NIC : Emulex Corporation OneConnect 10Gb NIC (be3)
      
      Patch Applied  %usr   %nice    %sys %iowait    %irq   %soft  %steal  %guest  %gnice   %idle  throughput
      Single Queue, 2 vCPU's
      -------------
      Before Patch :all    0.19    0.00    0.16    0.07    0.04    0.10    0.00    0.18    0.00   99.26  57864.18
      After  Patch :all    0.99    0.00    0.64    0.69    0.07    0.26    0.00    1.58    0.00   95.77  57735.77
      
      With 2 Queues, 2 vCPU's
      ---------------
      Before Patch :all    0.19    0.00    0.19    0.10    0.04    0.11    0.00    0.28    0.00   99.08  63083.09
      After  Patch :all    0.87    0.00    0.73    0.78    0.09    0.35    0.00    2.04    0.00   95.14  62917.03
      
      With 4 Queues, 4 vCPU's
      --------------
      Before Patch :all    0.20    0.00    0.21    0.11    0.04    0.12    0.00    0.32    0.00   99.00  80865.06
      After  Patch :all    0.71    0.00    0.93    0.85    0.11    0.51    0.00    2.62    0.00   94.27  86463.19
      
      With 8 Queues, 8 vCPU's
      --------------
      Before Patch :all    0.19    0.00    0.18    0.09    0.04    0.11    0.00    0.23    0.00   99.17  86795.31
      After  Patch :all    0.65    0.00    1.18    0.93    0.13    0.68    0.00    3.38    0.00   93.05  89459.93
      
      With 16 Queues, 8 vCPU's
      --------------
      After  Patch :all    0.61    0.00    1.59    0.97    0.18    0.92    0.00    4.32    0.00   91.41  120951.60
      ====================
      Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
      d2c60b13
    • Pankaj Gupta's avatar
      tuntap: Increase the number of queues in tun. · baf71c5c
      Pankaj Gupta authored
      
      
      Networking under kvm works best if we allocate a per-vCPU RX and TX
      queue in a virtual NIC. This requires a per-vCPU queue on the host side.
      
      It is now safe to increase the maximum number of queues.
      Preceding patch: 'net: allow large number of rx queues'
      made sure this won't cause failures due to high order memory
      allocations. Increase it to 256: this is the max number of vCPUs
      KVM supports.
      
      Size of tun_struct changes from 8512 to 10496 after this patch. This keeps
      pages allocated for tun_struct before and after the patch to 3.
      Signed-off-by: default avatarPankaj Gupta <pagupta@redhat.com>
      Reviewed-by: default avatarDavid Gibson <dgibson@redhat.com>
      Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
      baf71c5c
    • Pankaj Gupta's avatar
      net: allow large number of rx queues · 10595902
      Pankaj Gupta authored
      
      
      netif_alloc_rx_queues() uses kcalloc() to allocate memory
      for "struct netdev_queue *_rx" array.
      If we are doing large rx queue allocation kcalloc() might
      fail, so this patch does a fallback to vzalloc().
      Similar implementation is done for tx queue allocation in
      netif_alloc_netdev_queues().
      
      We avoid failure of high order memory allocation
      with the help of vzalloc(), this allows us to do large
      rx and tx queue allocation which in turn helps us to
      increase the number of queues in tun.
      
      As vmalloc() adds overhead on a critical network path,
      __GFP_REPEAT flag is used with kzalloc() to do this fallback
      only when really needed.
      Signed-off-by: default avatarPankaj Gupta <pagupta@redhat.com>
      Reviewed-by: default avatarMichael S. Tsirkin <mst@redhat.com>
      Reviewed-by: default avatarDavid Gibson <dgibson@redhat.com>
      Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
      10595902
    • Kenneth Williams's avatar
      team: Remove dead code · e350a96e
      Kenneth Williams authored
      
      
      The deleted lines are called from a function which is called:
      1) Only through __team_options_register via team_options_register and
      2) Only during initialization / mode initialization when there are no
      ports attached.
      Therefore the ports list is guarenteed to be empty and this code will
      never be executed.
      Signed-off-by: default avatarKenneth Williams <ken@williamsclan.us>
      Acked-by: default avatarJiri Pirko <jiri@resnulli.us>
      Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
      e350a96e
    • David Decotigny's avatar
      b1e8bc61