1. 24 5月, 2016 1 次提交
  2. 20 5月, 2016 25 次提交
  3. 19 5月, 2016 1 次提交
  4. 13 5月, 2016 1 次提交
    • C
      KVM: halt_polling: provide a way to qualify wakeups during poll · 3491caf2
      Christian Borntraeger 提交于
      Some wakeups should not be considered a sucessful poll. For example on
      s390 I/O interrupts are usually floating, which means that _ALL_ CPUs
      would be considered runnable - letting all vCPUs poll all the time for
      transactional like workload, even if one vCPU would be enough.
      This can result in huge CPU usage for large guests.
      This patch lets architectures provide a way to qualify wakeups if they
      should be considered a good/bad wakeups in regard to polls.
      
      For s390 the implementation will fence of halt polling for anything but
      known good, single vCPU events. The s390 implementation for floating
      interrupts does a wakeup for one vCPU, but the interrupt will be delivered
      by whatever CPU checks first for a pending interrupt. We prefer the
      woken up CPU by marking the poll of this CPU as "good" poll.
      This code will also mark several other wakeup reasons like IPI or
      expired timers as "good". This will of course also mark some events as
      not sucessful. As  KVM on z runs always as a 2nd level hypervisor,
      we prefer to not poll, unless we are really sure, though.
      
      This patch successfully limits the CPU usage for cases like uperf 1byte
      transactional ping pong workload or wakeup heavy workload like OLTP
      while still providing a proper speedup.
      
      This also introduced a new vcpu stat "halt_poll_no_tuning" that marks
      wakeups that are considered not good for polling.
      Signed-off-by: NChristian Borntraeger <borntraeger@de.ibm.com>
      Acked-by: Radim Krčmář <rkrcmar@redhat.com> (for an earlier version)
      Cc: David Matlack <dmatlack@google.com>
      Cc: Wanpeng Li <kernellwp@gmail.com>
      [Rename config symbol. - Paolo]
      Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>
      3491caf2
  5. 12 5月, 2016 4 次提交
  6. 03 5月, 2016 6 次提交
  7. 20 4月, 2016 1 次提交
    • P
      KVM: add missing memory barrier in kvm_{make,check}_request · 2e4682ba
      Paolo Bonzini 提交于
      kvm_make_request and kvm_check_request imply a producer-consumer
      relationship; add implicit memory barriers to them.  There was indeed
      already a place that was adding an explicit smp_mb() to order between
      kvm_check_request and the processing of the request.  That memory
      barrier can be removed (as an added benefit, kvm_check_request can use
      smp_mb__after_atomic which is free on x86).
      Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>
      2e4682ba
  8. 08 4月, 2016 1 次提交
    • A
      GRE: Disable segmentation offloads w/ CSUM and we are encapsulated via FOU · a0ca153f
      Alexander Duyck 提交于
      This patch fixes an issue I found in which we were dropping frames if we
      had enabled checksums on GRE headers that were encapsulated by either FOU
      or GUE.  Without this patch I was barely able to get 1 Gb/s of throughput.
      With this patch applied I am now at least getting around 6 Gb/s.
      
      The issue is due to the fact that with FOU or GUE applied we do not provide
      a transport offset pointing to the GRE header, nor do we offload it in
      software as the GRE header is completely skipped by GSO and treated like a
      VXLAN or GENEVE type header.  As such we need to prevent the stack from
      generating it and also prevent GRE from generating it via any interface we
      create.
      
      Fixes: c3483384 ("gro: Allow tunnel stacking in the case of FOU/GUE")
      Signed-off-by: NAlexander Duyck <aduyck@mirantis.com>
      Signed-off-by: NDavid S. Miller <davem@davemloft.net>
      a0ca153f