On 11/05/16 17:16, John Baldwin wrote: > On Saturday, November 05, 2016 04:30:43 PM Sean Bruno wrote: >> Author: sbruno >> Date: Sat Nov 5 16:30:42 2016 >> New Revision: 308345 >> URL: https://svnweb.freebsd.org/changeset/base/308345 >> >> Log: >> r295133 attempted to deactivate TSO in the 100Mbit link case with this >> adapter to work around bugs in TSO handling at this speed. >> >> em_init_locked is called during first boot of the adapter and will >> see that link_speed is unitialized, effectively turning off tso for >> all cards at all speeds, which I believe was *not* the intent. >> >> Move the handling of TSO deactivation to the link handler where we can >> more effectively make the decision about what to do. In addition, >> completely purge the TSO capabilities instead of disabling just CSUM_TSO. >> >> Thanks to jhb for explanation of the hw capabilites api. >> >> Thanks to royger and cognet for testing the 100Mbit failure case to >> ensure that their adapters do indeed still work. >> >> MFC after: 1 week >> Sponsored by: Limelight Networks >> >> Modified: >> head/sys/dev/e1000/if_em.c >> >> Modified: head/sys/dev/e1000/if_em.c >> ============================================================================== >> --- head/sys/dev/e1000/if_em.c Sat Nov 5 16:23:33 2016 >> (r308344) >> +++ head/sys/dev/e1000/if_em.c Sat Nov 5 16:30:42 2016 >> (r308345) >> @@ -369,11 +369,6 @@ MODULE_DEPEND(em, netmap, 1, 1, 1); >> #define MAX_INTS_PER_SEC 8000 >> #define DEFAULT_ITR (1000000000/(MAX_INTS_PER_SEC * 256)) >> >> -/* Allow common code without TSO */ >> -#ifndef CSUM_TSO >> -#define CSUM_TSO 0 >> -#endif >> - >> #define TSO_WORKAROUND 4 >> >> static SYSCTL_NODE(_hw, OID_AUTO, em, CTLFLAG_RD, 0, "EM driver >> parameters"); >> @@ -1396,15 +1391,9 @@ em_init_locked(struct adapter *adapter) >> if_clearhwassist(ifp); >> if (if_getcapenable(ifp) & IFCAP_TXCSUM) >> if_sethwassistbits(ifp, CSUM_TCP | CSUM_UDP, 0); >> - /* >> - ** There have proven to be problems with TSO when not >> - ** at full gigabit speed, so disable the assist automatically >> - ** when at lower speeds. -jfv >> - */ >> - if (if_getcapenable(ifp) & IFCAP_TSO4) { >> - if (adapter->link_speed == SPEED_1000) >> - if_sethwassistbits(ifp, CSUM_TSO, 0); >> - } >> + >> + if (if_getcapenable(ifp) & IFCAP_TSO4) >> + if_sethwassistbits(ifp, CSUM_TSO, 0); > > Does this always disable TSO? Should this part be removed entirely? > (That is, it seems like this would disable TSO even on Gigabit links). >
I was confused by this question. The old code *always* disabled TSO
because link_speed was always 0 here on boot. My intention is to ensure
that CSUM_TSO is set if IFCAP_TSO4 is set.
>> /* Configure for OS presence */
>> em_init_manageability(adapter);
>> @@ -2412,6 +2401,18 @@ em_update_link_status(struct adapter *ad
>> if (link_check && (adapter->link_active == 0)) {
>> e1000_get_speed_and_duplex(hw, &adapter->link_speed,
>> &adapter->link_duplex);
>> + /*
>> + ** There have proven to be problems with TSO when not
>> + ** at full gigabit speed, so disable the assist automatically
>> + ** when at lower speeds. -jfv
>> + */
>> + if (adapter->link_speed != SPEED_1000) {
>> + if_sethwassistbits(ifp, 0, CSUM_TSO);
>> + if_setcapenablebit(ifp, 0, IFCAP_TSO4);
>> + if_setcapabilitiesbit(ifp, 0, IFCAP_TSO4);
>> +
>> + }
>
> Even though I suggested it, I wonder if it wouldn't be better to only
> modify if_capenable and not if_capabilities, that way the admin can
> decide to use 'ifconfig em0 tso' to force it back on (e.g. if moving
> an adapter from 100 to 1G).
>
I spent several hours trying to come up with logic that would allow me
to allow the user to do this. I am open to suggestions here, but it
would require quite a bit more finesse than my "big hammer" approach.
sean
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