Dear Adrian Chadd,
Thanks for your reply. It's correct that USB may introduce some delays, but in our experiment we use mini-pcie devices indeed... Cesar At 2016-06-29 04:05:32, "Adrian Chadd" <adr...@freebsd.org> wrote: >Hi, > >can you try this using pci/pcie devices instead of USB? There may be >USB scheduling things in the way. > >On 27 June 2016 at 20:55, Cesar <caesa...@163.com> wrote: >> Hello all, >> We’ve recently tried to test packet injection performace in ath9k monitor >> mode. We set 2 laptops in monitor mode , PC 1 send a 500 Byte packets out, >> and PC 2 return a 500 Bytes packet back at once when it receives the packet >> of PC 1. Then we measured the RTT time and found it's about 1000us !!! >> >> Test environment: >> NIC: AR9287 >> driver: ath9k >> system: ubuntu 14.04 with kernel 3.14.57 >> send rate : at a fixed rate 54Mb >> >> >> We tried to send packets as "low" as possible in driver stack, and we're >> sure that we disabled the CCA and backoff using flags below: >> >> AR_DIAG_FORCE_CH_IDLE_HIGH >> AR_DIAG_IGNORE_VIRT_CS >> AR_D_GBL_IFS_MISC_IGNORE_BACKOFF >> >> besides we change the aifs to 1 and cwmin cwmax to 0 in ath_txq_setup to >> ensure there's no backoff. we even put our laptaps to a underground garage >> where channel is almost clean.But the test results is still about 1000us.... >> >> We've been stucked for serveral months, Any suggestion? >> Any feedback welcome... >> Thnkz in advance!!! >> >> Cesar >> >> >> >> >> >> >> >> _______________________________________________ >> ath9k-devel mailing list >> ath9k-devel@lists.ath9k.org >> https://lists.ath9k.org/mailman/listinfo/ath9k-devel >>
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