[Libevent-users] libevent 2.1.8 stable, delay in timer expiry.

[ravi chandran <ravigct27@xxxxxxxxx>]

Hi,

    Recently we upgraded to libevent 2.1.8-stable version, Previously we were using libevent 2.0.22.  We have a 1millisecond timer expiry event which is added to the event loop via evtimer_add() function.  Our Target supports High resolution timer(running linux OS), so in 2.0.22 this 1millisec timer expiry was happening properly.

 After our upstep to 2.1.8-stable version, the timer expiry is always happen after ~10millisec instead of 1 millisec. Even i tried changing the 1millisec timer to 4 or 5millisec, but expiry happen always after ~10millisec.  I added a time stamp inside the 1millisec expiry event callback and attached the output taken in 2.0.22 as well as in 2.1.8

Please find below the sample taken for 1 second period.

Some changes in function event_add_nolock_() through which this event_add() was done, but not sure if something was broken there.

Any patches related to this , please let me know.

Thank you,

Ravi

Timestamp output inside 1millisec expiry event callback(in libevent 2.1.8)

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

curTime.s= 91 nanoSec = 291946120

curTime.s= 91 nanoSec = 300174100 

curTime.s= 91 nanoSec = 310433820 

curTime.s= 91 nanoSec = 320771380   

curTime.s= 91 nanoSec = 331495340  

curTime.s= 91 nanoSec = 341155500   

curTime.s= 91 nanoSec = 350347880

curTime.s= 91 nanoSec = 360548820

curTime.s= 91 nanoSec = 370515980

curTime.s= 91 nanoSec = 380214960

curTime.s= 91 nanoSec = 390411420

curTime.s= 91 nanoSec = 400647280

curTime.s= 91 nanoSec = 411095860

curTime.s= 91 nanoSec = 420297780

curTime.s= 91 nanoSec = 430489360

curTime.s= 91 nanoSec = 440872460

curTime.s= 91 nanoSec = 450089980

curTime.s= 91 nanoSec = 460287080

curTime.s= 91 nanoSec = 470282320

curTime.s= 91 nanoSec = 480594280

curTime.s= 91 nanoSec = 490721080

curTime.s= 91 nanoSec = 501707460

curTime.s= 91 nanoSec = 510924240

curTime.s= 91 nanoSec = 520135820

curTime.s= 91 nanoSec = 530174060

curTime.s= 91 nanoSec = 541357920

curTime.s= 91 nanoSec = 550631740

curTime.s= 91 nanoSec = 560832100

curTime.s= 91 nanoSec = 570328020

curTime.s= 91 nanoSec = 580728600

curTime.s= 91 nanoSec = 590372100

curTime.s= 91 nanoSec = 600575200

curTime.s= 91 nanoSec = 610530960

curTime.s= 91 nanoSec = 620735320

curTime.s= 91 nanoSec = 631860380

curTime.s= 91 nanoSec = 640098480

curTime.s= 91 nanoSec = 650301780

curTime.s= 91 nanoSec = 660511100

curTime.s= 91 nanoSec = 670713940

curTime.s= 91 nanoSec = 680908940

curTime.s= 91 nanoSec = 690173600

curTime.s= 91 nanoSec = 700377960

curTime.s= 91 nanoSec = 710261240

curTime.s= 91 nanoSec = 720498140

curTime.s= 91 nanoSec = 730115280

curTime.s= 91 nanoSec = 740327480

curTime.s= 91 nanoSec = 750554900

curTime.s= 91 nanoSec = 760806900

curTime.s= 91 nanoSec = 771038420

curTime.s= 91 nanoSec = 780301520

curTime.s= 91 nanoSec = 790523040

curTime.s= 91 nanoSec = 800720420

curTime.s= 91 nanoSec = 810905400

curTime.s= 91 nanoSec = 820634140

curTime.s= 91 nanoSec = 830120860

curTime.s= 91 nanoSec = 840568980

curTime.s= 91 nanoSec = 850783440

curTime.s= 91 nanoSec = 860977400

curTime.s= 91 nanoSec = 870098360

curTime.s= 91 nanoSec = 880151500

curTime.s= 91 nanoSec = 890599720

curTime.s= 91 nanoSec = 900811620

curTime.s= 91 nanoSec = 910304900

curTime.s= 91 nanoSec = 951015200

curTime.s= 91 nanoSec = 960279420

curTime.s= 91 nanoSec = 970366480

curTime.s= 91 nanoSec = 980425660

curTime.s= 91 nanoSec = 990636840

Timestamp output inside 1millisec expiry event callback(in libevent 2.0.22)

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

curtime sec= 119, nanosec=149242140

curtime sec= 119, nanosec=150288680

curtime sec= 119, nanosec=151330020

curtime sec= 119, nanosec=152368900

curtime sec= 119, nanosec=153407060

curtime sec= 119, nanosec=154443960

curtime sec= 119, nanosec=155480260

curtime sec= 119, nanosec=156518900

curtime sec= 119, nanosec=157555540

curtime sec= 119, nanosec=158592120

curtime sec= 119, nanosec=159628520

curtime sec= 119, nanosec=160665600

curtime sec= 119, nanosec=161703780

curtime sec= 119, nanosec=162739960

curtime sec= 119, nanosec=163776660

curtime sec= 119, nanosec=164812800

curtime sec= 119, nanosec=165848440

curtime sec= 119, nanosec=166888440

curtime sec= 119, nanosec=167925580

curtime sec= 119, nanosec=168961360

curtime sec= 119, nanosec=169996580

curtime sec= 119, nanosec=171054640

curtime sec= 119, nanosec=172096200

curtime sec= 119, nanosec=173134840

curtime sec= 119, nanosec=174171900

curtime sec= 119, nanosec=175208660

curtime sec= 119, nanosec=176244720

curtime sec= 119, nanosec=177283760

curtime sec= 119, nanosec=178320160

curtime sec= 119, nanosec=179355320

curtime sec= 119, nanosec=180392900

curtime sec= 119, nanosec=181429440

curtime sec= 119, nanosec=182466720

curtime sec= 119, nanosec=183502540

curtime sec= 119, nanosec=184537540

curtime sec= 119, nanosec=185572880

curtime sec= 119, nanosec=186608180

curtime sec= 119, nanosec=187649560

curtime sec= 119, nanosec=188691320

curtime sec= 119, nanosec=189729560

curtime sec= 119, nanosec=190790820

curtime sec= 119, nanosec=191973380

curtime sec= 119, nanosec=193015160

curtime sec= 119, nanosec=194051560

curtime sec= 119, nanosec=195087980

curtime sec= 119, nanosec=196124080

curtime sec= 119, nanosec=197160140

curtime sec= 119, nanosec=198198820

curtime sec= 119, nanosec=199235520

curtime sec= 119, nanosec=200274040

curtime sec= 119, nanosec=201314580

curtime sec= 119, nanosec=202352900

curtime sec= 119, nanosec=203394540

curtime sec= 119, nanosec=204434240

curtime sec= 119, nanosec=205472600

curtime sec= 119, nanosec=206509400

curtime sec= 119, nanosec=207550720

curtime sec= 119, nanosec=208639980

curtime sec= 119, nanosec=209676620

curtime sec= 119, nanosec=210713600

curtime sec= 119, nanosec=211858860

curtime sec= 119, nanosec=212897600

curtime sec= 119, nanosec=213935940

curtime sec= 119, nanosec=214971620

curtime sec= 119, nanosec=216007600

curtime sec= 119, nanosec=217044720

curtime sec= 119, nanosec=218081480

curtime sec= 119, nanosec=219118760

curtime sec= 119, nanosec=220157140

curtime sec= 119, nanosec=221208800

curtime sec= 119, nanosec=222244720

curtime sec= 119, nanosec=223280780

curtime sec= 119, nanosec=224320380

curtime sec= 119, nanosec=225359280

curtime sec= 119, nanosec=226395980

curtime sec= 119, nanosec=227431720

curtime sec= 119, nanosec=228467420

curtime sec= 119, nanosec=229505340

curtime sec= 119, nanosec=230542780

curtime sec= 119, nanosec=231579460

curtime sec= 119, nanosec=232615460

curtime sec= 119, nanosec=233650900

curtime sec= 119, nanosec=234688640

curtime sec= 119, nanosec=235725120

curtime sec= 119, nanosec=236761760

curtime sec= 119, nanosec=237797140

curtime sec= 119, nanosec=238833460

curtime sec= 119, nanosec=239872620

curtime sec= 119, nanosec=240912240

curtime sec= 119, nanosec=242107460

curtime sec= 119, nanosec=243146760

.

.