[lttv.git] / ltt / branches / poly / doc / developer / lttng-atomic-up.txt


Atomic UP test results.


using test-time-probe2.ko

Clock speed : cpu MHz         : 3000.077

Tracing inactive

[  125.787229] test init
[  125.787303] test results : time per probe
[  125.787306] number of loops : 20000
[  125.787309] total time : 204413
[  125.787312] test end
[  175.660402] test init
[  175.660475] test results : time per probe
[  175.660479] number of loops : 20000
[  175.660482] total time : 203468
[  175.660484] test end
[  179.337362] test init
[  179.337436] test results : time per probe
[  179.337440] number of loops : 20000
[  179.337443] total time : 204757
[  179.337446] test end

Res : 10.21 cycles per loop

Atomic UP, one trace, flight recorder.

[  357.983971] test init
[  357.988837] test results : time per probe
[  357.988843] number of loops : 20000
[  357.988846] total time : 12349013
[  357.988849] test end
[  358.718896] test init
[  358.723049] test results : time per probe
[  358.723053] number of loops : 20000
[  358.723057] total time : 12332497
[  358.723059] test end
[  359.422038] test init
[  359.426173] test results : time per probe
[  359.426179] number of loops : 20000
[  359.426182] total time : 12332535
[  359.426185] test end

Res : 616.90 cycles per loop.
205.63 ns per loop

Atomic SMP, one trace, flight.


[  111.694180] test init
[  111.700191] test results : time per probe
[  111.700198] number of loops : 20000
[  111.700201] total time : 16925670
[  111.700204] test end
[  112.285716] test init
[  112.291321] test results : time per probe
[  112.291326] number of loops : 20000
[  112.291329] total time : 16766633
[  112.291332] test end
[  112.880602] test init
[  112.884739] test results : time per probe
[  112.884743] number of loops : 20000
[  112.884746] total time : 12358237
[  112.884748] test end

Res : 767.51 cycles per loop
255.83 ns per loop

(205.63-255.83)/255.83 * 100% = 19.62 %


Difference between
cmpxchg 2967855/20000 = 148.39 cycles or 49.46 ns
cmpxchg-up 540577/20000 = 27.02 cycles or 9.00 ns
irq save/restore 12636562/20000 = 631.82 cycles 210.60 ns


Mathieu Desnoyers, November 2006
Commit	Line	Data
d7d9a4ce	1
	2	Atomic UP test results.
	3
	4
	5
	6
	7	using test-time-probe2.ko
	8
	9	Clock speed : cpu MHz : 3000.077
	10
	11	Tracing inactive
	12
	13	[ 125.787229] test init
	14	[ 125.787303] test results : time per probe
	15	[ 125.787306] number of loops : 20000
	16	[ 125.787309] total time : 204413
	17	[ 125.787312] test end
	18	[ 175.660402] test init
	19	[ 175.660475] test results : time per probe
	20	[ 175.660479] number of loops : 20000
	21	[ 175.660482] total time : 203468
	22	[ 175.660484] test end
	23	[ 179.337362] test init
	24	[ 179.337436] test results : time per probe
	25	[ 179.337440] number of loops : 20000
	26	[ 179.337443] total time : 204757
	27	[ 179.337446] test end
	28
	29	Res : 10.21 cycles per loop
	30
	31	Atomic UP, one trace, flight recorder.
	32
	33	[ 357.983971] test init
	34	[ 357.988837] test results : time per probe
	35	[ 357.988843] number of loops : 20000
	36	[ 357.988846] total time : 12349013
	37	[ 357.988849] test end
	38	[ 358.718896] test init
	39	[ 358.723049] test results : time per probe
	40	[ 358.723053] number of loops : 20000
	41	[ 358.723057] total time : 12332497
	42	[ 358.723059] test end
	43	[ 359.422038] test init
	44	[ 359.426173] test results : time per probe
	45	[ 359.426179] number of loops : 20000
	46	[ 359.426182] total time : 12332535
	47	[ 359.426185] test end
	48
	49	Res : 616.90 cycles per loop.
	50	205.63 ns per loop
	51
	52	Atomic SMP, one trace, flight.
	53
	54
	55	[ 111.694180] test init
	56	[ 111.700191] test results : time per probe
	57	[ 111.700198] number of loops : 20000
	58	[ 111.700201] total time : 16925670
	59	[ 111.700204] test end
	60	[ 112.285716] test init
	61	[ 112.291321] test results : time per probe
	62	[ 112.291326] number of loops : 20000
	63	[ 112.291329] total time : 16766633
	64	[ 112.291332] test end
65	[ 112.880602] test init
66	[ 112.884739] test results : time per probe
67	[ 112.884743] number of loops : 20000
68	[ 112.884746] total time : 12358237
69	[ 112.884748] test end
70
71	Res : 767.51 cycles per loop
72	255.83 ns per loop
73
74	(205.63-255.83)/255.83 * 100% = 19.62 %
75
3fa56475	76
	77	Difference between
	78	cmpxchg 2967855/20000 = 148.39 cycles or 49.46 ns
	79	cmpxchg-up 540577/20000 = 27.02 cycles or 9.00 ns
	80	irq save/restore 12636562/20000 = 631.82 cycles 210.60 ns
	81
	82
	83
	84
	85
	86
d7d9a4ce	87	Mathieu Desnoyers, November 2006