Re: [dpdk-dev] [PATCH 0/7] typo, doc, simple fixes and some optimizations

[Honnappa Nagarahalli <Honnappa.Nagarahalli@arm.com>]

<snip>

> 
> On Tue, Oct 8, 2019 at 11:12 PM Honnappa Nagarahalli
> <honnappa.nagarahalli@arm.com> wrote:
> >
> > Few typo fixes, some corrections to the documentation and simple fixes
> > to the test cases.
> >
> > The last 2 commits contain simple optimizations with good amount of
> > performance improvements.
> 
> Do you have numbers to illustrate?
Thanks David.
I do not have the numbers for 'least acknowledged token' optimization. The performance test case to test that requires a different design in the performance test cases with additional code. This additional code is nothing but the rte_rcu_qsbr_defer_xxx APIs I am working on. I will be able to publish the numbers with and without this optimization.

I have the performance numbers for the last patch.

Without the patch:
===============
Total RCU updates = 11205362514
Cycles per 1000 updates: 587
Total RCU checks = 20000000
Cycles per 1000 checks: 29946

Perf Test: 12 Readers
Total RCU updates = 1200000000
Cycles per 1000 updates: 425

Perf test: 12 Writers ('wait' in qsbr_check == false)
Total RCU checks = 240000000
Cycles per 1000 checks: 319   <<<<<<<<<============== (see the improvement below)

Perf test: 1 writer, 12 readers, 1 QSBR variable, 1 QSBR Query, Blocking QSBR Check
Following numbers include calls to rte_hash functions
Cycles per 1 update(online/update/offline): 5857
Cycles per 1 check(start, check): 5889

Perf test: 1 writer, 12 readers, 1 QSBR variable, 1 QSBR Query, Non-Blocking QSBR check
Following numbers include calls to rte_hash functions
Cycles per 1 update(online/update/offline): 5859
Cycles per 1 check(start, check): 5891

With patch:
==========
Total RCU updates = 11075332503
Cycles per 1000 updates: 601
Total RCU checks = 20000000
Cycles per 1000 checks: 30265

Perf Test: 12 Readers
Total RCU updates = 1200000000
Cycles per 1000 updates: 425

Perf test: 12 Writers ('wait' in qsbr_check == false)
Total RCU checks = 240000000
Cycles per 1000 checks: 79   <<<<==================  (Improvement)

Perf test: 1 writer, 12 readers, 1 QSBR variable, 1 QSBR Query, Blocking QSBR Check
Following numbers include calls to rte_hash functions
Cycles per 1 update(online/update/offline): 5847
Cycles per 1 check(start, check): 5897

Perf test: 1 writer, 12 readers, 1 QSBR variable, 1 QSBR Query, Non-Blocking QSBR check
Following numbers include calls to rte_hash functions
Cycles per 1 update(online/update/offline): 5851
Cycles per 1 check(start, check): 5894

> 
> >
> > v2:
> >   All instances of size_t fixed (Ruifeng)
> >
> > Honnappa Nagarahalli (7):
> >   doc/rcu: fix typos
> >   doc/rcu: correct the limitation on number of threads
> >   doc/rcu: add information about storing token and resource
> >   test/rcu: use size_t instead of int
> >   test/rcu: use correct nomenclature while printing results
> >   lib/rcu: add least acknowledged token optimization
> >   lib/rcu: update QS only when there are updates from writer
> 
> Series applied, thanks.
> 
> 
> --
> David Marchand