1. 19 Dec, 2013 4 commits
    • Daniel Borkmann's avatar
      net: skbuff: improve comment on checksumming · 78ea85f1
      Daniel Borkmann authored
      It can be a bit confusing when looking for checksumming flags that
      the actual comment for this resides elsewhere further below in the
      header file.
      
      Thus, bring the documentation where we define these flags, and
      slightly improve the doc text to make it a bit more clear/readable.
      
      Also, whitespace-align values of the define while at it.
      Signed-off-by: default avatarDaniel Borkmann <dborkman@redhat.com>
      Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
      78ea85f1
    • Terry Lam's avatar
      net-qdisc-hhf: Heavy-Hitter Filter (HHF) qdisc · 10239edf
      Terry Lam authored
      This patch implements the first size-based qdisc that attempts to
      differentiate between small flows and heavy-hitters.  The goal is to
      catch the heavy-hitters and move them to a separate queue with less
      priority so that bulk traffic does not affect the latency of critical
      traffic.  Currently "less priority" means less weight (2:1 in
      particular) in a Weighted Deficit Round Robin (WDRR) scheduler.
      
      In essence, this patch addresses the "delay-bloat" problem due to
      bloated buffers. In some systems, large queues may be necessary for
      obtaining CPU efficiency, or due to the presence of unresponsive
      traffic like UDP, or just a large number of connections with each
      having a small amount of outstanding traffic. In these circumstances,
      HHF aims to reduce the HoL blocking for latency sensitive traffic,
      while not impacting the queues built up by bulk traffic.  HHF can also
      be used in conjunction with other AQM mechanisms such as CoDel.
      
      To capture heavy-hitters, we implement the "multi-stage filter" design
      in the following paper:
      C. Estan and G. Varghese, "New Directions in Traffic Measurement and
      Accounting", in ACM SIGCOMM, 2002.
      
      Some configurable qdisc settings through 'tc':
      - hhf_reset_timeout: period to reset counter values in the multi-stage
                           filter (default 40ms)
      - hhf_admit_bytes:   threshold to classify heavy-hitters
                           (default 128KB)
      - hhf_evict_timeout: threshold to evict idle heavy-hitters
                           (default 1s)
      - hhf_non_hh_weight: Weighted Deficit Round Robin (WDRR) weight for
                           non-heavy-hitters (default 2)
      - hh_flows_limit:    max number of heavy-hitter flow entries
                           (default 2048)
      
      Note that the ratio between hhf_admit_bytes and hhf_reset_timeout
      reflects the bandwidth of heavy-hitters that we attempt to capture
      (25Mbps with the above default settings).
      
      The false negative rate (heavy-hitter flows getting away unclassified)
      is zero by the design of the multi-stage filter algorithm.
      With 100 heavy-hitter flows, using four hashes and 4000 counters yields
      a false positive rate (non-heavy-hitters mistakenly classified as
      heavy-hitters) of less than 1e-4.
      Signed-off-by: default avatarTerry Lam <vtlam@google.com>
      Acked-by: default avatarEric Dumazet <edumazet@google.com>
      Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
      10239edf
    • Matthew Whitehead's avatar
      3c59x: Add software timestamping · 2a2529ef
      Matthew Whitehead authored
      Added software timestamping ability. Tested with linuxptp and synchronized
      clocks to an average of less than 200 microseconds on 10 megabit ethernet.
      
      Tested on both Vortex and Boomerang models.
      Signed-off-by: default avatarMatthew Whitehead <tedheadster@gmail.com>
      Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
      2a2529ef
    • Francesco Fusco's avatar
      lib: hash: follow-up fixups for arch hash · 23721754
      Francesco Fusco authored
      This patch adds the include file to pull in __read_mostly on some
      architectures e.g. ppc and also fixes up signatures in generic
      asm.
      Reported-by: default avatarFengguang Wu <fengguang.wu@intel.com>
      Signed-off-by: default avatarFrancesco Fusco <ffusco@redhat.com>
      Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
      23721754
  2. 18 Dec, 2013 36 commits