On 09/06/2011 01:56 PM, Arnaud Charlet wrote:
this means using as many processes as there are CPUs, right? It seems pretty
Right, but only for gnattools, which is a relatively short time, and
which always occurs at the end of the build (so with nothing else
running at the same time).
dubious to me to use more processes than the user maybe asked for. For example
I have to restrict the number of CPUs used when building GCC to less than I have
since otherwise my machine overheats and turns itself off. Is there some way
to get at the -j level the user passed to the top-level make and use that?
No, I'm not aware of a way to get this information.
The solution would be to support running gnatmake as a client of make's
job server. In short:
1) gnatmake should look for the MAKEFLAGS environment variable, and look
for the --jobserver-fds= option found inside it. The option receives a
comma-separated list of two file descriptors. The first is an "input"
pipe, the second is an "output" pipe.
2) before invoking any child process, gnatmake should ensure the child
doesn't see the two pipes (unless the child were also an instance of
make/gnatmake).
3) *after* invoking any child process, gnatmake should perform a
blocking 1-byte read from the "input" pipe.
4) after reaping any child process, gnatmake should perform a blocking
1-byte write to the "output" pipe.
5) you should add a + in front of rules that use gnatmake.
Paolo
