Update laysim-GR740 v0.11 & Real-Time Performance & Cycle Accuracy (II)

 

Update laysim-GR740 v0.11 & Real-Time Performance & Cycle Accuracy (II)

laysim-GR740 is updated to v0.11 in order to enhance the real-time performance under the SMP environment which utilizes almost 100% CPU load of GR740.

The performance of laysim-gr740-dbt v0.11 is improved by 23% on average, and the real-time performance of SMPLOCK01 is improved by 35.85% compared to v0.10 for example.

Despite the performance improvement of laysim-gr740-dbt, it still doesn't satisfy the performance of GR740 under the SMP environment. 

KARI/FSW team is developing a new processor emulator which based on multi-thread framework with DBT to satisfy the real-time performance of GR740 multicores. It will allocate each core of the GR740 processor to each core of x64 respectively, and achieve maximum performance with minimal synchronization among each cores. (But it will require at least 6 cores of x64 host.)

1. Test Environment

The performance and cycle accuracy of laysim-GR740 were measured on Intel i7-6700K @4.00GHz CentOS 7 64bit (4 cores and 8GB RAM) under VMware Workstation 15 Pro. And Its performance and cycle accuracy were compared with GR740 development board and TSIM3-LEON4 3.0.0 evaluation version. Since TSIM3-LEON4 3.0.0 evaluation version from Gaisler only operates as FAST UART, some codes are modified to block UART output in order to exclude the cycle effect of UART model.

2. Dhrystone Performance & Cycle Accuracy

Dhrystone benchmark with 1000000 was compiled -O3 option using BCC-2.1.0 without UART output.

1) Single Dhrystone

The raw MIPS of laysim-gr740-dbt v0.11 shows 469 MIPS with 100.23% cycle accuracy.

Table 1. Single Dhrystone Performance & Cycle Accuracy

Dhrystone (No UART)	# of INST	Wall Clock (ms)	RAW MIPS	Real-Time Performance (%)	Cycles	Cycle Accuracy (%)
GR740 (250MHz)	334010144	1724.134784	193.73	100	431033696	100
laysim-gr740	334010146	13262.1	25.19	13	434026883	100.69
laysim-gr740-dbt v0.10	334010146	887.238	376.46	194.33	432016291	100.23
laysim-gr740-dbt v0.11	334010146	712.172	469	242.1	432016291	100.23
TSIM3-LEON4 Eval.	334010146	10520	31.75	16.39	436030672	101.16

2) Two Instances of Dhrystone

When two instances of Dhrystone were executed as AMP application on laysim-gr740-dbt v0.11, it shows 488.35 raw MIPS and its real-time performance is 126.93%. It can meet the real-time performance of GR740.

Table 2. Two Instances of Dhrystone Performance & Cycle Accuracy

Dhrystone 2 (No UART)	# of INST	Wall Clock (ms)	RAW MIPS	Real-Time Performance (%)	Cycles	Cycle Accuracy (%)
GR740 (250MHz)	668011065	1736.242072	384.75	100	431033696	100
laysim-gr740	668001729	25918.9	25.77	6.7	434026940	100.69
laysim-gr740-dbt v0.10	668001729	1868.28	357.55	92.93	432016303	100.23
laysim-gr740-dbt v0.11	668001729	1367.88	488.35	126.93	432016303	100.23
TSIM3-LEON4 Eval.	668009384	25590	26.1	6.78	466049427	108.12

3) Three Instances of Dhrystone

When three instances of Dhrystone were executed as AMP application on laysim-gr740-dbt v0.11, it shows 491.02 raw MIPS and its real-time performance is 86.73%. It cannot meet the real-time performance of the GR740.

Table 3. Three Instances of Dhrystone Performance & Cycle Accuracy

Dhrystone 3 (No UART)	# of INST	Wall Clock (ms)	RAW MIPS	Real-Time Performance (%)	Cycles	Cycle Accuracy (%)
GR740 (250MHz)	1002012942	1769.840384	566.16	100	442460096	100
laysim-gr740	1001993306	35060.1	28.58	5.05	434026939	98.09
laysim-gr740-dbt v0.10	1001993306	2901.21	345.37	61	432016303	97.64
laysim-gr740-dbt v0.11	1001993306	2040.63	491.02	86.73	432016303	97.64
TSIM3-LEON4 Eval.	1002007211	47930	20.91	3.69	549074177	124.1

4) Four Instances of Dhrystone

When four instances of Dhrystone were executed as AMP application on laysim-gr740-dbt v0.11, it shows 471.93 raw MIPS and its real-time performance is 63.73%. It cannot meet the real-time performance of the GR740.

Table 4. Four Instances of Dhrystone Performance & Cycle Accuracy

Dhrystone 4 (No UART)	# of INST	Wall Clock (ms)	RAW MIPS	Real-Time Performance (%)	Cycles	Cycle Accuracy (%)
GR740 (250MHz)	1336013374	1792.693464	745.25	100	448173366	100
laysim-gr740	1335984884	43686.3	30.58	4.1	434026939	96.84
laysim-gr740-dbt v0.10	1335984884	4057.63	329.25	44.18	432016303	96.39
laysim-gr740-dbt v0.11	1335984884	2830.92	471.93	63.33	432016303	96.39
TSIM3-LEON4 Eval.	1336006537	69320	19.27	2.59	704097695	157.1

5) Overall RAW MIPS of Dhrystone

Figure 1 shows the overall RAW MIPS of Dhrystone on GR740, laysim-gr740, laysim-gr740-dbt v0.10/v0.11 and TSIM3-LEON4 evaluation. The peak raw MIPS of laysim-gr740-dbt is 491.02 raw MIPS, and it can reach 471.93 raw MIPS on four cores.

Figure 1. Overall RAW MIPS of Dhrystone

6) Overall Real-Time Performance & Cycle Accuracy of Dhrystone

Figure 2 shows the overall real-time performance and cycle accuracy of Dhrystone on GR740, laysim-gr740, laysim-gr740-dbt v0.10/v0.11 and TSIM3-LEON4 evaluation. When a single core of GR740 only works, laysim-gr740-dbt outperforms the real-time performance of GR740. And when two cores of GR740 are running, laysim-gr740-dbt shows 126.93% of the real-time performance of GR740. However, when three or more cores of GR740 are running, laysim-gr740-dbt shows approximately 87.73%/63.33% of the real-time performance of GR740.

Figure 2. Overall Real-Time Performance & Cycle Accuracy of Dhrystone

3. Stanford Performance & Cycle Accuracy

Stanford benchmark was compiled -O3 option using BCC-2.1.0 without UART output.

1) Single Stanford

The raw MIPS of laysim-gr740-dbt v0.11 shows 366.21 MIPS with 99.55% cycle accuracy.

Table 5. Single Stanford Performance & Cycle Accuracy

Stanford (No UART)	# of INST	Wall Clock (ms)	RAW MIPS	Real-Time Performance (%)	Cycles	Cycle Accuracy (%)
GR740 (250MHz)	13058448	70.518936	185.18	100	17629734	100
laysim-gr740	13059162	529.573	24.66	13.32	19307982	109.52
laysim-gr740-dbt v0.10	13059162	46.584	280.34	151.38	17550748	99.55
laysim-gr740-dbt v0.11	13059162	35.66	366.21	197.75	17551004	99.55
TSIM3-LEON4 Eval.	13059162	410	31.85	17.2	17546760	99.53

2) Two Instances of Stanford

When two instances of Stanford were executed as AMP application on laysim-gr740-dbt v0.11, it shows 389.36 raw MIPS and its real-time performance is 107.83%. It can meet the real-time performance of GR740.

Table 6. Two Instances of Stanford Performance & Cycle Accuracy

Stanford 2 (No UART)	# of INST	Wall Clock (ms)	RAW MIPS	Real-Time Performance (%)	Cycles	Cycle Accuracy (%)
GR740 (250MHz)	26021084	71.84244	362.2	100	17960610	100
laysim-gr740	25940333	1024.33	25.32	7.01	19251110	107.19
laysim-gr740-dbt v0.10	25940333	101.84	254.72	70.54	17550760	97.72
laysim-gr740-dbt v0.11	25940333	66.623	389.36	107.83	17551016	97.72
TSIM3-LEON4 Eval.	26003474	910	28.58	7.89	18451460	102.73

3) Three Instances of Stanford

When three instances of Stanford were executed as AMP application on laysim-gr740-dbt v0.11, it shows 395.28 raw MIPS and its real-time performance is 74.66%. It cannot meet the real-time performance of the GR740.

Table 7. Three Instances of Stanford Performance & Cycle Accuracy

Stanford 3 (No UART)	# of INST	Wall Clock (ms)	RAW MIPS	Real-Time Performance (%)	Cycles	Cycle Accuracy (%)
GR740 (250MHz)	38989561	73.32266	531.75	100	18330665	100
laysim-gr740	38821500	1353.49	28.68	5.42	19251110	105.02
laysim-gr740-dbt v0.10	38821500	146.684	264.66	49.99	17550760	95.75
laysim-gr740-dbt v0.11	38821500	98.213	395.28	74.66	17551016	95.75
TSIM3-LEON4 Eval.	38967675	1560	24.98	4.7	20529851	112

4) Four Instances of Stanford

When four instances of Stanford were executed as AMP application on laysim-gr740-dbt v0.11, it shows 388.13 raw MIPS and its real-time performance is 56.06%. It cannot meet the real-time performance of the GR740.

Table 8. Four Instances of Stanford Performance & Cycle Accuracy

Stanford 4 (No UART)	# of INST	Wall Clock (ms)	RAW MIPS	Real-Time Performance (%)	Cycles	Cycle Accuracy (%)
GR740 (250MHz)	52019296	74.676784	696.59	100	18669196	100
laysim-gr740	51702667	1654.37	31.25	4.51	19251110	103.12
laysim-gr740-dbt v0.10	51702667	197.023	262.42	37.9	17550760	94.01
laysim-gr740-dbt v0.11	51702667	133.208	388.13	56.06	17551016	94.01
TSIM3-LEON4 Eval.	51802687	2210	23.44	3.38	23022597	123.32

5) Overall RAW MIPS of Stanford

Figure 3 shows the overall RAW MIPS of Stanford on GR740, laysim-gr740, laysim-gr740-dbt v0.10/v0.11 and TSIM3-LEON4 evaluation. The peak raw MIPS of laysim-gr740-dbt is 395.28 raw MIPS, and it can reach 388.13 raw MIPS on four cores.

Figure 3. Overall RAW MIPS of Stanford

6) Overall Real-Time Performance & Cycle Accuracy of Stanford

Figure 5 shows the overall real-time performance and cycle accuracy of Stanford on GR740, laysim-gr740, laysim-gr740-dbt v0.10/v0.11 and TSIM3-LEON4 evaluation. When a single core of GR740 only works, laysim-gr740-dbt outperforms the real-time performance of GR740. And when two cores of GR740 are running, laysim-gr740-dbt shows 107.83% of the real-time performance of GR740. However, when three or more cores of GR740 are running, laysim-gr740-dbt shows approximately 74.66%/56.06% of the real-time performance of GR740.

Figure 4. Overall Real-Time Performance & Cycle Accuracy of Standford

4. RTEMS 5.1.0-RC1 SMP testsuites Performance & Cycle Accuracy

Four examples of SMP testsuites of RTEMS 5.1.0-RC1 (SMPATOMIC01, SMPSCHEDAFFINITY05, SMPSCHEDEDF03, SMPLOCK01) which are modified to block UART output in order to exclude the cycle effect of UART model are executed on GR740, laysim-gr740, laysim-gr740-dbt and TSIM3-LEON4 evaluation. Four examples use all cores of GR740 and their CPU load is almost 100%.

Figure 5. Real-Time Performance & Cycle Accuracy of RTEMS 5.1.0-RC1 SMP testsuites

1) SMPATOMIC01

When the SMPATOMIC01 was executed on laysim-GR740, GR740 board and TSIM3-LEON4 evaluation, the performance and cycle accuracy are shown in Table 9 below. 

The real-time performance of laysim-gr740-dbt v0.11 shows 75.04% with 100.77% cycle accuracy.

Table 9. Performance & Cycle Accuracy of SMPATOMIC01

SMPATOMIC01 (No UART)	Cycles	Wall Clock (ms)	Real-Time Performance (%)	Cycle Accuracy (%)
GR740 (250MHz)	2006127689	8024.510756	100	100
laysim-gr740	2024286135	117206	6.85	100.91
laysim-gr740-dbt v0.10	2021498061	17204.6	46.64	100.77
laysim-gr740-dbt v0.11	2021502063	10693.5	75.04	100.77
TSIM3-LEON4 Eval.	2005935360	49830	16.1	99.99

2) SMPSCHEDAFFINITY05

When the SMPSCHEDAFFINITY05 was executed on laysim-GR740, GR740 board and TSIM3-LEON4 evaluation, the performance and cycle accuracy are shown in Table 10 below. 

The real-time performance of laysim-gr740-dbt v0.11 shows 39.11% with 97.74% cycle accuracy.

Table 10. Performance & Cycle Accuracy of SMPSCHEDAFFINITY05 

SMPSCHEDAFFINITY05 (No UART)	Cycles	Wall Clock (ms)	Real-Time Performance (%)	Cycle Accuracy (%)
GR740 (250MHz)	400436415	1601.74566	100	100
laysim-gr740	394066491	49295.8	3.25	98.41
laysim-gr740-dbt v0.10	393881315	7233.16	22.14	98.36
laysim-gr740-dbt v0.11	391381962	4095.75	39.11	97.74
TSIM3-LEON4 Eval.	396375290	47340	3.38	98.99

3) SMPSCHEDEDF03

When the SMPSCHEDEDF03 was executed on laysim-GR740, GR740 board and TSIM3-LEON4 evaluation, the performance and cycle accuracy are shown in Table 11 below. 

The real-time performance of laysim-gr740-dbt v0.11 shows 29.75% with 100.52% cycle accuracy.

Table 11. Performance & Cycle Accuracy of SMPSCHEDEDF03 

SMPSCHEDEDF03 (No UART)	Cycles	Wall Clock (ms)	Real-Time Performance (%)	Cycle Accuracy (%)
GR740 (250MHz)	2505455209	10021.82084	100	100
laysim-gr740	2522118284	280431	3.57	100.67
laysim-gr740-dbt v0.10	2518399718	56309.3	17.8	100.52
laysim-gr740-dbt v0.11	2518376018	33690.3	29.75	100.52
TSIM3-LEON4 Eval.	2505025973	281330	3.56	99.98

4) SMPLOCK01

When the SMPLOCK01 was executed on laysim-GR740, GR740 board and TSIM3-LEON4 evaluation, the performance and cycle accuracy are shown in Table 12 below. 

The real-time performance of laysim-gr740-dbt v0.11 shows 72.75% with 100.2% cycle accuracy.

Table 12. Performance & Cycle Accuracy of SMPLOCK01

SMPLOCK01 (No UART)	Cycles	Wall Clock (ms)	Real-Time Performance (%)	Cycle Accuracy (%)
GR740 (250MHz)	7751233127	31004.93251	100	100
laysim-gr740	7769405801	561058	5.53	100.23
laysim-gr740-dbt v0.10	7766562010	84027.1	36.9	100.2
laysim-gr740-dbt v0.11	7766564818	42615.9	72.75	100.2
TSIM3-LEON4 Eval.	4294967040	313090	9.9	55.41

5. Conclusion and Future Work Again!

Although laysim-gr740-dbt which uses the dynamic binary translation (JIT) shows the high performance and correct cycle accuracy for GR740 processor, but it cannot satisfy the real-time performance of GR740 under the SMP environment. Its peak performance is about 75.04% and it shows 55.16% performance at average under the SMP environment which utilizes almost 100% CPU load of GR740.

A new GR740 processor emulator which adopting the multi-thread framework with DBT is being developed by KARI/FSW team. However, in the process of development, it is not easy to control each x64 core to synchronize emulated LEON4 core without loosing performance. But development will still continue!