Messages in this thread | | | Date | Fri, 20 Jan 2006 00:42:19 +0000 (GMT) | From | Mel Gorman <> | Subject | Re: [PATCH 0/5] Reducing fragmentation using zones |
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On Thu, 19 Jan 2006, Joel Schopp wrote:
> > Benchmark comparison between -mm+NoOOM tree and with the new zones > > I know you had also previously posted a very simplified version of your real > fragmentation avoidance patches. I was curious if you could repost those with > the other benchmarks for a 3 way comparison. The simplified version got rid > of a lot of the complexity people were complaining about and in my mind still > seems like preferable direction. >
To satisfy this request, I did a quick rebase of the list-based approach against 2.6.16-rc1-mm1 to have a comparable set of benchmarks. I will post the patches in the morning after a re-read.
The results here are in three sets
Set 1: -mm3 Vs list-based anti-frag Set 2: -mm3 Vs zone-based anti-frag Set 3: list-based anti-frag Vs zone-based anti-frag
In the headers, list-based is called mbuddy-v22. Zone based is called zbuddy-v3 (versions 1 and 2 were only posted to lhms-devel)
>>> BEGIN SET 1: -clean Vs mbuddy-v22 <<< 2.6.16-rc1-mm1-clean 2.6.16-rc1-mm1-mbuddy-v22 Time taken to extract kernel: 14 15 Time taken to build kernel: 741 741
2.6.16-rc1-mm1-clean 2.6.16-rc1-mm1-mbuddy-v22 1 creat-clo 12273.11 12239.80 -33.31 -0.27% File Creations and Closes/second 2 page_test 131762.75 134311.90 2549.15 1.93% System Allocations & Pages/second 3 brk_test 586206.90 597167.14 10960.24 1.87% System Memory Allocations/second 4 jmp_test 4375520.75 4373004.50 -2516.25 -0.06% Non-local gotos/second 5 signal_test 79436.76 77307.56 -2129.20 -2.68% Signal Traps/second 6 exec_test 62.90 62.93 0.03 0.05% Program Loads/second 7 fork_test 1211.92 1218.13 6.21 0.51% Task Creations/second 8 link_test 4332.30 4324.56 -7.74 -0.18% Link/Unlink Pairs/second
2.6.16-rc1-mm1-clean 2.6.16-rc1-mm1-mbuddy-v22 Order 10 10 Allocation type HighMem HighMem Attempted allocations 275 275 Success allocs 60 86 Failed allocs 215 189 DMA zone allocs 1 1 Normal zone allocs 5 0 HighMem zone allocs 54 85 EasyRclm zone allocs 0 0 % Success 21 31 HighAlloc Under Load Test Results Pass 2 2.6.16-rc1-mm1-clean 2.6.16-rc1-mm1-mbuddy-v22 Order 10 10 Allocation type HighMem HighMem Attempted allocations 275 275 Success allocs 101 103 Failed allocs 174 172 DMA zone allocs 1 1 Normal zone allocs 5 0 HighMem zone allocs 95 102 EasyRclm zone allocs 0 0 % Success 36 37 HighAlloc Test Results while Rested 2.6.16-rc1-mm1-clean 2.6.16-rc1-mm1-mbuddy-v22 Order 10 10 Allocation type HighMem HighMem Attempted allocations 275 275 Success allocs 141 242 Failed allocs 134 33 DMA zone allocs 1 1 Normal zone allocs 16 83 HighMem zone allocs 124 158 EasyRclm zone allocs 0 0 % Success 51 88 >>> END SET 1: -clean Vs mbuddy-v22 <<<
>>> BEGIN SET 2: -clean Vs zbuddy-v3 <<< 2.6.16-rc1-mm1-clean 2.6.16-rc1-mm1-zbuddy-v3 Time taken to extract kernel: 14 14 Time taken to build kernel: 741 738
2.6.16-rc1-mm1-clean 2.6.16-rc1-mm1-zbuddy-v3 1 creat-clo 12273.11 12235.72 -37.39 -0.30% File Creations and Closes/second 2 page_test 131762.75 132946.18 1183.43 0.90% System Allocations & Pages/second 3 brk_test 586206.90 603298.90 17092.00 2.92% System Memory Allocations/second 4 jmp_test 4375520.75 4376557.81 1037.06 0.02% Non-local gotos/second 5 signal_test 79436.76 81086.49 1649.73 2.08% Signal Traps/second 6 exec_test 62.90 62.81 -0.09 -0.14% Program Loads/second 7 fork_test 1211.92 1212.52 0.60 0.05% Task Creations/second 8 link_test 4332.30 4346.60 14.30 0.33% Link/Unlink Pairs/second
2.6.16-rc1-mm1-clean 2.6.16-rc1-mm1-zbuddy-v3 Order 10 10 Allocation type HighMem HighMem Attempted allocations 275 275 Success allocs 60 106 Failed allocs 215 169 DMA zone allocs 1 1 Normal zone allocs 5 8 HighMem zone allocs 54 0 EasyRclm zone allocs 0 97 % Success 21 38 HighAlloc Under Load Test Results Pass 2 2.6.16-rc1-mm1-clean 2.6.16-rc1-mm1-zbuddy-v3 Order 10 10 Allocation type HighMem HighMem Attempted allocations 275 275 Success allocs 101 154 Failed allocs 174 121 DMA zone allocs 1 1 Normal zone allocs 5 8 HighMem zone allocs 95 0 EasyRclm zone allocs 0 145 % Success 36 56 HighAlloc Test Results while Rested 2.6.16-rc1-mm1-clean 2.6.16-rc1-mm1-zbuddy-v3 Order 10 10 Allocation type HighMem HighMem Attempted allocations 275 275 Success allocs 141 212 Failed allocs 134 63 DMA zone allocs 1 1 Normal zone allocs 16 8 HighMem zone allocs 124 0 EasyRclm zone allocs 0 203 % Success 51 77
>>> BEGIN SET 2: -clean Vs zbuddy-v3 <<<
>>> BEGIN SET 3: -mbuddy-v22 Vs zbuddy-v3 <<< 2.6.16-rc1-mm1-mbuddy-v22 2.6.16-rc1-mm1-zbuddy-v3 Time taken to extract kernel: 15 14 Time taken to build kernel: 741 738
2.6.16-rc1-mm1-mbuddy-v22 2.6.16-rc1-mm1-zbuddy-v3 1 creat-clo 12239.80 12235.72 -4.08 -0.03% File Creations and Closes/second 2 page_test 134311.90 132946.18 -1365.72 -1.02% System Allocations & Pages/second 3 brk_test 597167.14 603298.90 6131.76 1.03% System Memory Allocations/second 4 jmp_test 4373004.50 4376557.81 3553.31 0.08% Non-local gotos/second 5 signal_test 77307.56 81086.49 3778.93 4.89% Signal Traps/second 6 exec_test 62.93 62.81 -0.12 -0.19% Program Loads/second 7 fork_test 1218.13 1212.52 -5.61 -0.46% Task Creations/second 8 link_test 4324.56 4346.60 22.04 0.51% Link/Unlink Pairs/second
2.6.16-rc1-mm1-mbuddy-v22 2.6.16-rc1-mm1-zbuddy-v3 Order 10 10 Allocation type HighMem HighMem Attempted allocations 275 275 Success allocs 86 106 Failed allocs 189 169 DMA zone allocs 1 1 Normal zone allocs 0 8 HighMem zone allocs 85 0 EasyRclm zone allocs 0 97 % Success 31 38 HighAlloc Under Load Test Results Pass 2 2.6.16-rc1-mm1-mbuddy-v22 2.6.16-rc1-mm1-zbuddy-v3 Order 10 10 Allocation type HighMem HighMem Attempted allocations 275 275 Success allocs 103 154 Failed allocs 172 121 DMA zone allocs 1 1 Normal zone allocs 0 8 HighMem zone allocs 102 0 EasyRclm zone allocs 0 145 % Success 37 56 HighAlloc Test Results while Rested 2.6.16-rc1-mm1-mbuddy-v22 2.6.16-rc1-mm1-zbuddy-v3 Order 10 10 Allocation type HighMem HighMem Attempted allocations 275 275 Success allocs 242 212 Failed allocs 33 63 DMA zone allocs 1 1 Normal zone allocs 83 8 HighMem zone allocs 158 0 EasyRclm zone allocs 0 203 % Success 88 77
>>> END SET 3: -mbuddy-v22 Vs zbuddy-v3 <<<
So, in terms of performance on this set of tests, both approachs perform roughly the same as the stock kernel in terms of absolute performance. In terms of high-order allocations, zone-based appears to do better under load. However, if you look at the zones that are used, you will see that zone-based appears to do as well as list-based *only* because it has the EASYRCLM zone to play with. list-based was way better at keeping the normal zone defragmented as well as highmem which is especially obvious when tested at rest. list-based was able to allocate 83 huge pages from ZONE_NORMAL at rest while zone-based only managed 8.
Secondly, zone-based requires careful configuration to be successful. If booted with kernelcore=896MB for example, it only performs slightly better than the standard kernel. If booted with kernelcore=1024MB, it tends to perform slightly worse (more zone fallbacks I guess) and still only manages slighly better satisfaction of high order pages.
On the flip side, zone-based code changes are easier to understand than the list-based ones (at least in terms of volume of code changes). The zone-based gives guarantees on what will happen in the future while list-based is best-effort.
In terms of fragmentation, I still think that list-based is better overall without configuration. The results above also represent the best possible configuration with zone-based versus no configuration at all against list-based. In an environment with changing workloads a constant reality, I bet that list-based would win overall.
> Zone based approaches are runtime inflexible and require boot time tuning by > the sysadmin. There are lots of workloads that "reasonable" defaults for a > zone based approach would cause the system to regress terribly. > > -Joel >
-- Mel Gorman Part-time Phd Student Linux Technology Center University of Limerick IBM Dublin Software Lab - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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