Re: [ath9k-devel] ath9k: massive unexplained latency in 2.6.27 (rc5, rc6, probably others)

Steven Noonan
2008-09-23T07:55:48Z

2008/9/23 Steven Noonan <steven@uplinklabs.net>:> On Mon, Sep 22, 2008 at 9:01 AM, Luis R. Rodriguez> <lrodriguez@atheros.com> wrote:>> On Mon, Sep 22, 2008 at 8:11 AM, Steven Noonan <steven@uplinklabs.net> wrote:>>> On Mon, Sep 22, 2008 at 1:06 AM, Luis R. Rodriguez>>> <lrodriguez@atheros.com> wrote:>>>> Please test the following patch.>>>>>>>> diff --git a/drivers/net/wireless/ath9k/core.c b/drivers/net/wireless/ath9k/core.c>>>> index c262ef2..9a51739 100644>>>> --- a/drivers/net/wireless/ath9k/core.c>>>> +++ b/drivers/net/wireless/ath9k/core.c>>>> @@ -681,10 +681,12 @@ int ath_open(struct ath_softc *sc, struct ath9k_channel *initial_chan)>>>> * Enable MIB interrupts when there are hardware phy counters.>>>> * Note we only do this (at the moment) for station mode.>>>> */>>>> +#if 0>>>> if (ath9k_hw_phycounters(ah) &&>>>> ((sc->sc_ah->ah_opmode == ATH9K_M_STA) ||>>>> (sc->sc_ah->ah_opmode == ATH9K_M_IBSS)))>>>> sc->sc_imask |= ATH9K_INT_MIB;>>>> +#endif>>>> /*>>>> * Some hardware processes the TIM IE and fires an>>>> * interrupt when the TIM bit is set. For hardware>>>>>>>>>> It didn't apply to -rc7, but I managed to apply it manually>>> (apparently you made this for wireless-testing?) and added the #if 0.>>> After 7 hours uptime with the driver, no apparent interrupt storm.>>>>>> I'll do more thorough testing later, but I have a 3 hour drive today,>>> and some packing to do, so it'll need to wait a bit.>>>> Yeah I did it for wireless-testing. Good to hear this so far has>> solved the issue. I'll port it to 27 and post it once I get your>> blessings that this fixed it by a Tested-by.>>>> Okay. I'm in Seattle now.>> Yes, it solved the issue, but surely an #if 0 isn't a proper solution.> What's the actual bug here? I'm afraid the meaning of what's going on> here isn't exactly intuitive.>> Also, I'm doing an 8 hour run with this patch tonight. Maybe more,> depends on when I wake up. ;)>> I think if this resolves the issue on two separate ≈8 hour runs, it> should be considered the solution to the issue, unless it resurfaces.>
I am only 25 minutes into the run, but I feel this is worth reportingbefore I forget. No IRQ storm thus far, but the connection keepsdropping. Or rather, it doesn't disassociate, but while I wastransferring a large file, it had points of time where it suddenlylost and reacquired the connection (signal strength fluctuates wildlybetween 70-90% and then 0% for a second, and then back tofluctuating). Perhaps this is related to the lack of aggregation?
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