[PATCH ncns v1 0/4] chnet ring cleanups

[Ammar Faizi <ammarfaizi2@gnuweeb.org>]

Hi Al,

This series contains small cleanups and fixes. Summary:

1) Refactor SQE handling.

Make everything about SQE handling simpler and rename them to represent
the function purpose better.

2) Improve `PostCQE()` waiting mechanism.

Don't use sleep(1) in a loop to wait for the CQE slot be free, instead,
use a conditional variable to reduce the loop cycle and also to reduce
the latency because the wake up doesn't need to wait for a full second.
It just waits until it's signaled whenever the CQE slot becomes
available again.

3)  Make sure we are holding the lock when calling `cqe_size()`.

In `CNRingCtx::WaitCQE`, the first call to `cqe_size()` is not protected
by the cqe_lock. Protect it.

4) Only notify CQE free slot when it's available.

In `CNRingCtx::WaitCQE`, we don't actually always need to call
`NotifyWaitCQEFreeSlot()`. To reduce the call overhead, just check
whether the CQE slot is available or not. If it's available, then call
it, otherwise, just don't.

Signed-off-by: Ammar Faizi <ammarfaizi2@gnuweeb.org>
---

Ammar Faizi (4):
  chnet: ring: Refactor SQE handling
  chnet: ring: Improve `PostCQE()` waiting mechanism
  chnet: ring: Make sure we are holding the lock when calling `cqe_size()`
  chnet: ring: Only notify CQE free slot when it's available

 chnet/chnet_ring.cc | 198 +++++++++++++++++++++++++++++---------------
 chnet/chnet_ring.h  |  23 ++---
 2 files changed, 143 insertions(+), 78 deletions(-)


base-commit: 498d5a49cf6e372fa386c832caca4a64987ea78c
-- 
Ammar Faizi