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  1. 18 Jan, 2014 27 commits
  3. 17 Jan, 2014 13 commits
    • John W. Linville's avatar
      Merge branch 'master' of... · 7916a075
      John W. Linville authored 
      Merge branch 'master' of git://git.kernel.org/pub/scm/linux/kernel/git/linville/wireless-next into for-davem
      7916a075
    • David S. Miller's avatar
      Merge branch 'virtio_rx_merging' · cf84eb0b
      David S. Miller authored 
      Michael Dalton says:

====================
virtio-net: mergeable rx buffer size auto-tuning

The virtio-net device currently uses aligned MTU-sized mergeable receive
packet buffers. Network throughput for workloads with large average
packet size can be improved by posting larger receive packet buffers.
However, due to SKB truesize effects, posting large (e.g, PAGE_SIZE)
buffers reduces the throughput of workloads that do not benefit from GRO
and have no large inbound packets.

This patchset introduces virtio-net mergeable buffer size auto-tuning,
with buffer sizes ranging from aligned MTU-size to PAGE_SIZE. Packet
buffer size is chosen based on a per-receive queue EWMA of incoming
packet size.

To unify mergeable receive buffer memory allocation and improve
SKB frag coalescing, all mergeable buffer memory allocation is
migrated to per-receive queue page frag allocators.

The per-receive queue mergeable packet buffer size is exported via
sysfs, and the network device sysfs layer has been extended to add
support for device-specific per-receive queue sysfs attribute groups.
====================
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
      cf84eb0b
    • Michael Dalton's avatar
      virtio-net: initial rx sysfs support, export mergeable rx buffer size · fbf28d78
      Michael Dalton authored 
      Add initial support for per-rx queue sysfs attributes to virtio-net. If
mergeable packet buffers are enabled, adds a read-only mergeable packet
buffer size sysfs attribute for each RX queue.
Suggested-by: default avatarMichael S. Tsirkin <mst@redhat.com>
Acked-by: default avatarMichael S. Tsirkin <mst@redhat.com>
Signed-off-by: default avatarMichael Dalton <mwdalton@google.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
      fbf28d78
    • Michael Dalton's avatar
      lib: Ensure EWMA does not store wrong intermediate values · 03144b58
      Michael Dalton authored 
      To ensure ewma_read() without a lock returns a valid but possibly
out of date average, modify ewma_add() by using ACCESS_ONCE to prevent
intermediate wrong values from being written to avg->internal.
Suggested-by: default avatarEric Dumazet <eric.dumazet@gmail.com>
Acked-by: default avatarMichael S. Tsirkin <mst@redhat.com>
Acked-by: default avatarEric Dumazet <edumazet@google.com>
Signed-off-by: default avatarMichael Dalton <mwdalton@google.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
      03144b58
    • Michael Dalton's avatar
      net-sysfs: add support for device-specific rx queue sysfs attributes · a953be53
      Michael Dalton authored 
      Extend existing support for netdevice receive queue sysfs attributes to
permit a device-specific attribute group. Initial use case for this
support will be to allow the virtio-net device to export per-receive
queue mergeable receive buffer size.
Signed-off-by: default avatarMichael Dalton <mwdalton@google.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
      a953be53
    • Michael Dalton's avatar
      virtio-net: auto-tune mergeable rx buffer size for improved performance · ab7db917
      Michael Dalton authored 
      Commit 2613af0e ("virtio_net: migrate mergeable rx buffers to page frag
allocators") changed the mergeable receive buffer size from PAGE_SIZE to
MTU-size, introducing a single-stream regression for benchmarks with large
average packet size. There is no single optimal buffer size for all
workloads.  For workloads with packet size <= MTU bytes, MTU + virtio-net
header-sized buffers are preferred as larger buffers reduce the TCP window
due to SKB truesize. However, single-stream workloads with large average
packet sizes have higher throughput if larger (e.g., PAGE_SIZE) buffers
are used.

This commit auto-tunes the mergeable receiver buffer packet size by
choosing the packet buffer size based on an EWMA of the recent packet
sizes for the receive queue. Packet buffer sizes range from MTU_SIZE +
virtio-net header len to PAGE_SIZE. This improves throughput for
large packet workloads, as any workload with average packet size >=
PAGE_SIZE will use PAGE_SIZE buffers.

These optimizations interact positively with recent commit
ba275241 ("virtio-net: coalesce rx frags when possible during rx"),
which coalesces adjacent RX SKB fragments in virtio_net. The coalescing
optimizations benefit buffers of any size.

Benchmarks taken from an average of 5 netperf 30-second TCP_STREAM runs
between two QEMU VMs on a single physical machine. Each VM has two VCPUs
with all offloads & vhost enabled. All VMs and vhost threads run in a
single 4 CPU cgroup cpuset, using cgroups to ensure that other processes
in the system will not be scheduled on the benchmark CPUs. Trunk includes
SKB rx frag coalescing.

net-next w/ virtio_net before 2613af0e (PAGE_SIZE bufs): 14642.85Gb/s
net-next (MTU-size bufs):  13170.01Gb/s
net-next + auto-tune: 14555.94Gb/s

Jason Wang also reported a throughput increase on mlx4 from 22Gb/s
using MTU-sized buffers to about 26Gb/s using auto-tuning.
Signed-off-by: default avatarMichael Dalton <mwdalton@google.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
      ab7db917
    • Michael Dalton's avatar
      virtio-net: use per-receive queue page frag alloc for mergeable bufs · fb51879d
      Michael Dalton authored 
      The virtio-net driver currently uses netdev_alloc_frag() for GFP_ATOMIC
mergeable rx buffer allocations. This commit migrates virtio-net to use
per-receive queue page frags for GFP_ATOMIC allocation. This change unifies
mergeable rx buffer memory allocation, which now will use skb_refill_frag()
for both atomic and GFP-WAIT buffer allocations.

To address fragmentation concerns, if after buffer allocation there
is too little space left in the page frag to allocate a subsequent
buffer, the remaining space is added to the current allocated buffer
so that the remaining space can be used to store packet data.
Acked-by: default avatarMichael S. Tsirkin <mst@redhat.com>
Signed-off-by: default avatarMichael Dalton <mwdalton@google.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
      fb51879d
    • Michael Dalton's avatar
      net: allow > 0 order atomic page alloc in skb_page_frag_refill · 097b4f19
      Michael Dalton authored 
      skb_page_frag_refill currently permits only order-0 page allocs
unless GFP_WAIT is used. Change skb_page_frag_refill to attempt
higher-order page allocations whether or not GFP_WAIT is used. If
memory cannot be allocated, the allocator will fall back to
successively smaller page allocs (down to order-0 page allocs).

This change brings skb_page_frag_refill in line with the existing
page allocation strategy employed by netdev_alloc_frag, which attempts
higher-order page allocations whether or not GFP_WAIT is set, falling
back to successively lower-order page allocations on failure. Part
of migration of virtio-net to per-receive queue page frag allocators.
Acked-by: default avatarMichael S. Tsirkin <mst@redhat.com>
Acked-by: default avatarEric Dumazet <edumazet@google.com>
Signed-off-by: default avatarMichael Dalton <mwdalton@google.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
      097b4f19
    • Wei Yongjun's avatar
      net_sched: fix error return code in fw_change_attrs() · 722e47d7
      Wei Yongjun authored 
      The error code was not set if change indev fail, so the error
condition wasn't reflected in the return value. Fix to return a
negative error code from this error handling case instead of 0.

Fixes: 2519a602 ('net_sched: optimize tcf_match_indev()')
Signed-off-by: default avatarWei Yongjun <yongjun_wei@trendmicro.com.cn>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
      722e47d7
    • David S. Miller's avatar
      Merge branch 'tipc' · 8b88a11e
      David S. Miller authored 
      Ying Xue says:

====================
tipc: align TIPC behaviours of waiting for events with other stacks

Comparing the current implementations of waiting for events in TIPC
socket layer with other stacks, TIPC's behaviour is very different
because wait_event_interruptible_timeout()/wait_event_interruptible()
are always used by TIPC to wait for events while relevant socket or
port variables are fed to them as their arguments. As socket lock has
to be released temporarily before the two routines of waiting for
events are called, their arguments associated with socket or port
structures are out of socket lock protection. This might cause
serious issues where the process of calling socket syscall such as
sendsmg(), connect(), accept(), and recvmsg(), cannot be waken up
at all even if proper event arrives or improperly be woken up
although the condition of waking up the process is not satisfied
in practice.

Therefore, aligning its behaviours with similar functions implemented
in other stacks, for instance, sk_stream_wait_connect() and
inet_csk_wait_for_connect() etc, can avoid above risks for us.
====================
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
      8b88a11e
    • Ying Xue's avatar
      tipc: standardize recvmsg routine · 9bbb4ecc
      Ying Xue authored 
      Standardize the behaviour of waiting for events in TIPC recvmsg()
so that all variables of socket or port structures are protected
within socket lock, allowing the process of calling recvmsg() to
be woken up at appropriate time.
Signed-off-by: default avatarYing Xue <ying.xue@windriver.com>
Reviewed-by: default avatarJon Maloy <jon.maloy@ericsson.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
      9bbb4ecc
    • Ying Xue's avatar
      tipc: standardize sendmsg routine of connected socket · 391a6dd1
      Ying Xue authored 
      Standardize the behaviour of waiting for events in TIPC send_packet()
so that all variables of socket or port structures are protected within
socket lock, allowing the process of calling sendmsg() to be woken up
at appropriate time.
Signed-off-by: default avatarYing Xue <ying.xue@windriver.com>
Reviewed-by: default avatarJon Maloy <jon.maloy@ericsson.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
      391a6dd1
    • Ying Xue's avatar
      tipc: standardize sendmsg routine of connectionless socket · 3f40504f
      Ying Xue authored 
      Comparing the behaviour of how to wait for events in TIPC sendmsg()
with other stacks, the TIPC implementation might be perceived as
different, and sometimes even incorrect. For instance, sk_sleep()
and tport->congested variables associated with socket are exposed
without socket lock protection while wait_event_interruptible_timeout()
accesses them. So standardizing it with similar implementation
in other stacks can help us correct these errors which the process
of calling sendmsg() cannot be woken up event if an expected event
arrive at socket or improperly woken up although the wake condition
doesn't match.
Signed-off-by: default avatarYing Xue <ying.xue@windriver.com>
Reviewed-by: default avatarJon Maloy <jon.maloy@ericsson.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
      3f40504f
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