On Mon, 15 Apr 2019 12:24:47 +0000 "Ananyev, Konstantin" <konstantin.anan...@intel.com> wrote:
> > -----Original Message----- > > From: Stephen Hemminger [mailto:step...@networkplumber.org] > > Sent: Saturday, April 13, 2019 12:06 AM > > To: Honnappa Nagarahalli <honnappa.nagaraha...@arm.com> > > Cc: Ananyev, Konstantin <konstantin.anan...@intel.com>; > > paul...@linux.ibm.com; Kovacevic, Marko <marko.kovace...@intel.com>; > > dev@dpdk.org; Gavin Hu (Arm Technology China) <gavin...@arm.com>; Dharmik > > Thakkar <dharmik.thak...@arm.com>; Malvika Gupta > > <malvika.gu...@arm.com>; nd <n...@arm.com> > > Subject: Re: [PATCH v5 1/3] rcu: add RCU library supporting QSBR mechanism > > > > On Fri, 12 Apr 2019 22:24:45 +0000 > > Honnappa Nagarahalli <honnappa.nagaraha...@arm.com> wrote: > > > > > > > > > > On Fri, 12 Apr 2019 15:20:37 -0500 > > > > Honnappa Nagarahalli <honnappa.nagaraha...@arm.com> wrote: > > > > > > > > > Add RCU library supporting quiescent state based memory reclamation > > > > method. > > > > > This library helps identify the quiescent state of the reader threads > > > > > so that the writers can free the memory associated with the lock less > > > > > data structures. > > > > > > > > > > Signed-off-by: Honnappa Nagarahalli <honnappa.nagaraha...@arm.com> > > > > > Reviewed-by: Steve Capper <steve.cap...@arm.com> > > > > > Reviewed-by: Gavin Hu <gavin...@arm.com> > > > > > Reviewed-by: Ola Liljedahl <ola.liljed...@arm.com> > > > > > Acked-by: Konstantin Ananyev <konstantin.anan...@intel.com> > > > > > > > > After evaluating long term API/ABI issues, I think you need to get rid > > > > of almost > > > > all use of inline and visible structures. Yes it might be marginally > > > > slower, but > > > > you thank me the first time you have to fix something. > > > > > > > Agree, I was planning on another version to address this (I am yet to > > > take a look at your patch addressing the ABI). > > > The structure visibility definitely needs to be addressed. > > > For the inline functions, is the plan to convert all the inline functions > > > in DPDK? If yes, I think we need to consider the performance > > difference. May be consider L3-fwd application, change all the inline > > functions in its path and run a test? > > > > Every function that is not in the direct datapath should not be inline. > > Exceptions or things like rx/tx burst, ring enqueue/dequeue, and packet > > alloc/free > > Plus synchronization routines: spin/rwlock/barrier, etc. > I think rcu should be one of such exceptions - it is just another > synchronization mechanism after all > (just a bit more sophisticated). > Konstantin If you look at the other userspace RCU, you wil see that the only inlines are the rcu_read_lock,rcu_read_unlock and rcu_reference/rcu_assign_pointer. The synchronization logic is all real functions.
