Large page usage is primarily intended to provide performance improvements to large memory high performance computing applications by bringing larger blocks of memory into cache when memory is accessed. The benefits of large pages are mainly due to better hardware prefetch and fewer Translation Lookaside Buffer (TLB) misses.
| Node Type | Large page | Memory for large pages | Total Memory | Memory Available* |
|---|---|---|---|---|
| 1.3 GHz 32-processor Regatta | |
| | |
| 1.3 GHz 24-processor Regatta | |
| | |
| 1.7 GHz 32-processor Regatta | |
| | |
| 1.7 GHz 32-processor Regatta | |
| | |
| 1.5 GHz p655 | |
| |
* This includes memory for large pages. If you are not using large pages, subtract the amount of memory reserved for large pages from this number.
There are several ways to run executables using large pages. We recommend the following:
/usr/ccs/bin/ldedit -b lpdata ./a.out
./a.out
poe ./a.out
/usr/ccs/bin/ldedit -b nolpdata ./a.out
Below are examples of Loadleveler scripts for running an executable. Note
this script marks the executable for large pages. If it is already marked,
you can delete the ldedit command. You may want to umark the
executable for large pages after you run the executable.
#!/bin/csh #@ initialdir = /homes/r30/runesha/BENCHMARK/BENCH-SEPTEMBER-2002/TMJ/LargePages #@ input = test1.in #@ output = test1.out #@ error = test1.err #@ wall_clock_limit = 10:00:00 #@ resources = ConsumableMemory(500) #@ requirements = (Feature == "LargePages") #@ queue /usr/ccs/bin/ldedit -b lpdata ./a.out time ./a.out
#!/bin/csh #@ initialdir = /homes/r30/runesha/BENCHMARK/BENCH-SEPTEMBER-2002/TMJ/LargePages #@ output = mpi_$(jobid).out #@ error = mpi_$(jobid).err #@ job_type = parallel #@ wall_clock_limit = 1:00:00 #@ requirements = (Feature == "LargePages") #@ resources = ConsumableMemory(12000) #@ node = 1 #@ tasks_per_node = 2 #@ node_usage = shared #@ queue /usr/ccs/bin/ldedit -b lpdata ./main.x time poe ./main.x
This information is available in alternative formats upon request by individuals with disabilities. Please send email to alt-format@msi.umn.edu or call 612-624-0528. |
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