There have still been intermittent problems with apparent TX
hangs for some customers. These have been problematic to reproduce
but I believe these changes will address them. Testing on a number
of fronts have been positive.
EM: there is an important 'chicken bit' fix for 82574 in the shared
code this is supported in the core here.
- The TX path has been tightened up to improve performance. In
particular UDP with jumbo frames was having problems, and the
changes here have improved that.
- OACTIVE has been used more carefully on the theory that some
hangs may be due to a problem in this interaction
- Problems with the RX init code, the "lazy" allocation and
ring initialization has been found to cause problems in some
newer client systems, and as it really is not that big a win
(its not in a hot path) it seems best to remove it.
- HWTSO was broken when VLAN HWTAGGING or HWFILTER is used, I
found this was due to an error in setting up the descriptors
in em_xmit.
IGB:
- TX is also improved here. With multiqueue I realized its very
important to handle OACTIVE only under the CORE lock so there
are no races between the queues.
- Flow Control handling was broken in a couple ways, I have changed
and I hope improved that in this delta.
- UDP also had a problem in the TX path here, it was change to
improve that.
- On some hardware, with the driver static, a weird stray interrupt
seems to sometimes fire and cause a panic in the RX mbuf refresh
code. This is addressed by setting interrupts late in the init
path, and also to set all interrupts bits off at the start of that.
been undergoing test for some weeks. This improves the RX
mbuf handling to avoid system hang due to depletion. Thanks
to all those who have been testing the code, and to Beezar
Liu for the design changes.
Next the igb driver is updated for similar RX changes, but
also to add new features support for our upcoming i350 family
of adapters.
MFC after a week
- Add a single sysctl procedure to all three drivers to read an arbitrary
register (the register is passed as arg2). Use it to replace existing
routines in igb(4) that used a separate routine for each register, and
to add support for missing stats in em(4) and lem(4).
- Move the 'rx_overruns' and 'watchdog_timeouts' stats out of the MAC stats
section as they are driver stats, not MAC counters.
- Simplify the code that creates per-queue stats in igb(4) to use a single
loop and remove duplicated code.
- Properly read all 64 bits of the 'good octets received/transmitted' in
em(4) and lem(4).
- Actually read the interrupt count registers in em(4), and drop the
'host to card' sysctl stats from em(4) as they are not implemented in
any of the hardware this driver supports.
- Restore several stats to em(4) that were lost in the earlier stats
conversion including per-queue stats.
- Export several MAC stats in em(4) that were exported in igb(4) but not
in em(4).
- Export stats in lem(4) using individual sysctls as in em(4) and igb(4).
Reviewed by: jfv
MFC after: 1 week
configuration function. For failed memory allocations, em(4)/lem(4)
called panic(9) which is not acceptable on production box.
igb(4)/ixgb(4)/ix(4) allocated the required memory in stack which
consumed 768 bytes of stack memory which looks too big.
To address these issues, allocate multicast array memory in device
attach time and make multicast configuration success under any
conditions. This change also removes the excessive use of memory in
stack.
Reviewed by: jfv
em revision 7.0.0:
- Using driver devclass, seperate legacy (pre-pcie) code
into a seperate source file. This will at least help
protect against regression issues. It compiles along
with em, and is transparent to end use, devices in each
appear to be 'emX'. When using em in a modular form this
also allows the legacy stuff to be defined out.
- Add tx and rx rings as in igb, in the 82574 this becomes
actual multiqueue for the first time (2 queues) while in
other PCIE adapters its just make code cleaner.
- Add RX mbuf handling logic that matches igb, this will
eliminate packet drops due to temporary mbuf shortage.
igb revision 1.9.3:
- Following the ixgbe code, use a new approach in what
was called 'get_buf', the routine now has been made
independent of rxeof, it now does the update to the
engine TDT register, this design allows temporary
mbuf resources to become non-critical, not requiring
a packet to be discarded, instead it just returns and
does not increment the tail pointer.
- With the above change it was also unnecessary to keep
'spare' maps around, since we do not have the discard
issue.
- Performance tweaks and improvements to the code also.
MFC in a week
