Messages in this thread | | | Subject | Test results of context-switch under O(1) J9 scheduler | From | "Duc Vianney" <> | Date | Thu, 31 Jan 2002 16:21:18 -0600 |
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The O(1) J9 scheduler with changes to generic context-switch definitely provides the best context-switch latency time based on the lat_ctx test from LMBench benchmark. Test hardware was a 2-way SMP system with 512MB memory. The results obtained from a 2.4.17 SMP kernel built with O(1)J2, O(1)J4 and O(1)J9 versions, compared against 2.2.19 base and 2.4.17 base. The data are time in microsecs. In almost all test cases, context switches under O(1)J9 seem much faster than 2.4.17 base, and as fast as 2.2.19 (or better at heavy load). The 2.2.19 measurements were used as a reference point for 2.2.x.
Ratio of Base Base O(1)J2 O(1)J4 O(1)J9 O(1)J9 / Kernel 2.2.19 2.4.17 2.4.17 2.4.17 2.4.17 2417Base
lat_ctx -s 0 2 4 8 16 32 64 2 1.46 3.03 7.38 7.38 0.97 32.0% 4 2.04 3.55 4.84 4.89 4.97 140.2% 8 2.74 4.41 6.04 4.96 4.43 100.6% 16 3.01 4.78 4.93 5.46 3.82 80.0% 32 5.48 7.29 4.80 5.75 4.56 62.6% 64 5.74 8.37 5.86 6.12 5.62 67.1%
lat_ctx -s 16 2 4 8 16 32 64 2 14.33 16.15 15.62 15.11 13.93 86.3% 4 14.30 16.13 17.83 16.27 16.51 102.4% 8 14.39 16.38 17.58 17.35 15.20 92.8% 16 16.43 19.34 17.75 17.70 16.54 85.6% 32 39.92 39.93 24.63 24.95 32.65 81.8% 64 53.67 49.87 45.34 42.76 49.91 100.1%
lat_ctx -s 32 2 4 8 16 32 64 2 22.86 24.73 27.56 27.03 24.29 98.2% 4 22.85 24.85 25.98 25.78 25.22 101.5% 8 25.18 30.94 26.51 26.65 25.04 81.0% 16 58.70 74.32 38.69 35.07 48.32 65.0% 32 99.16 94.41 74.32 74.85 89.62 94.9% 64 99.28 96.91 98.45 97.75 94.29 97.3%
lat_ctx -s 64 2 4 8 16 32 64 2 40.24 42.06 44.57 44.11 40.72 96.8% 4 49.10 43.28 43.23 43.99 42.85 99.0% 8 111.28 105.56 49.43 45.81 58.41 55.3% 16 185.12 182.84 127.11 124.74 169.94 92.9% 32 185.20 182.81 184.97 182.92 175.70 96.1% 64 185.26 184.46 186.54 186.22 178.63 96.8%
Duc.
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