[Boost-build] [Boost][build][v2 head] Memory footprint

From: K. Noel Belcourt (kbelco_at_[hidden])
Date: 2006-09-05 00:42:26

Hi,

I just wanted to give you a feel for Bjam's memory footprint when  
building a reasonably large application.  On our Linux boxes

(uname -a) Linux machine 2.6.9-22.0.2.ELsmp #1 SMP Thu Jan 5 17:11:56  
EST 2006 x86_64 x86_64 x86_64 GNU/Linux

our build command
bjam --v2 -j3
...patience...
...found 61711 targets...
...updating 28632 targets...

left bjam with a 1.7Gb memory footprint, leaving very little memory  
for the build phase on this 2Gb machine.

top - 22:28:53 up 17 days, 12:31,  2 users,  load average: 1.55,  
1.07, 0.73
Tasks:  88 total,   7 running,  81 sleeping,   0 stopped,   0 zombie
Cpu(s): 75.7% us,  9.3% sy,  0.0% ni, 13.0% id,  0.5% wa,  0.2% hi,   
1.3% si
Mem:   2056420k total,  2042912k used,    13508k free,     4352k buffers
Swap:  4096564k total,    62792k used,  4033772k free,    85516k cached

   PID USER      PR  NI  VIRT  RES  SHR S %CPU %MEM    TIME+  COMMAND
6873 kbelco    17   0 42224  38m 2776 R 33.6  1.9   0:01.01 cc1plus
6882 kbelco    16   0 35100  31m 2656 R 23.9  1.6   0:00.72 cc1plus
6879 kbelco    16   0 32644  29m 2656 R 21.9  1.5   0:00.66 cc1plus
6858 kbelco    16   0  8324 1112  860 R  0.3  0.1   0:00.01 top
6564 kbelco    16   0 1739m 1.7g  524 S  0.0 85.1   6:18.45 bjam
6872 kbelco    17   0  1516  448  364 S  0.0  0.0   0:00.00 g++
6878 kbelco    17   0  1516  448  364 S  0.0  0.0   0:00.00 g++
6881 kbelco    18   0  1516  448  364 S  0.0  0.0   0:00.00 g++

Is there anyway I can get bjam to release some memory once the  
dependency analysis is complete and it moves into the build phase?   
With our applications, there are a significant number of dependencies  
and I understand it takes lots of memory to do the dependency  
analysis but I'd like to find a way to free up some memory for the  
compiles and links.  Many of our application exceed 500 Mb when  
linked debug and with bjam holding ~80% of memory, the builds and  
links run very slowly.

Any ideas?

-- Noel Belcourt