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| author | Daniel Halperin <dhalperi@cs.washington.edu> | 2011-03-17 03:16:36 +0100 |
|---|---|---|
| committer | Wey-Yi Guy <wey-yi.w.guy@intel.com> | 2011-03-25 14:57:50 +0100 |
| commit | 374920cb0512f5938fdf1f5af4f9afa7502dd0f9 (patch) | |
| tree | 8de1e768991818253240181ad4814d89ed2cd434 /Kbuild | |
| parent | iwlagn: fix aggregation queue scheduler setup (diff) | |
| download | linux-374920cb0512f5938fdf1f5af4f9afa7502dd0f9.tar.xz linux-374920cb0512f5938fdf1f5af4f9afa7502dd0f9.zip | |
iwlwifi: limit number of attempts for highest HT rate
When filling out its rate scale table, iwlwifi repeats the first HT rate
IWL_HT_NUMBER_TRY times. The hardware scheduler will stop using
aggregation for any frame that fails LINK_QUAL_AGG_DISABLE_START_DEF
times. Currently, both these constants equal 3.
If iwlwifi probes a faster rate than the link supports, all frames in a
(potentially tens of frames large) batch will fail IWL_HT_NUMBER_TRY
times. Because this happens to be as large as
LINK_QUAL_AGG_DISABLE_START_DEF, all frames will then be sent
individually. This leads to a short, but performance-degrading window
where the legacy stop-and-wait MAC takes over.
Bounding the initial rate by (LINK_QUAL_AGG_DISABLE_START_DEF-1)
attempts makes the third try use a lower rate and hence more be likely
to succeed. This somewhat mitigates the above described behavior.
Signed-off-by: Daniel Halperin <dhalperi@cs.washington.edu>
Signed-off-by: Wey-Yi Guy <wey-yi.w.guy@intel.com>
Diffstat (limited to 'Kbuild')
0 files changed, 0 insertions, 0 deletions