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1. That doesn't do what you think it does. From the manual: "A rule with multiple targets is equivalent to writing many rules, each with one target, and all ide

1. That doesn't do what you think it does. From the manual: "A rule with multiple targets is equivalent to writing many rules, each with one target, and all identical aside from that." It does not mean one rule that creates multiple targets. To achieve that, you need to use wildcards. For some reason, when using wildcards, the syntax is interpreted differently. 2. If I create a rule to create an intermediate file "b" from original file "a", then another rule to create file "c" that I want to keep from "b", but there is an error running the command that creates "c", then make will happily delete the intermediate "b" (which in my case took 27 hours to create) although it knows the final "c" wasn't created properly. This means that when I rerun make (having fixed the problem), that 27 hour process needs to be run again, which is a waste of my time. 3. I want to say "make -j 64" on my 64-thread server, and not have 64 64-thread processes start. But I also do want 64 single-threaded processes to run when possible. 4. By crash recovery, I mean that by default a process will start creating the target file. If someone yanks the power, that target file will be present, with a recent modified time, but incomplete. Make will assume the file was created fine, so when I rerun make it will try to perform the next step, which may take 10 hours to fail. I want make to notice that the command did not successfully complete, and restart it from scratch.

chubot 9y ago
I agree with all your criticisms, except I'm a bit confused about #3. Are you saying you're using Make with multi-threaded build actions? As far as I know, most compilers are single-threaded, so this isn't much of an issue in practice. But I'm curious where you've encountered this problem.
- mnw21cam 9y ago
  No, I was using make to process large files for bioinformatics. So, think 60GB (compressed) of sequencing data from a whole genome sequencing run, which comes as a set of ~800,000,000 individually sequenced short stretches of DNA in two files. A multi-threaded process converts that into a file containing the sequences and where they align in the human genome, and takes about a day. Once that job has been finished, other jobs can be kicked off to use the produced data. Overall, the build process is a DAG with several hundred individual jobs, and performing that in a make-like system helps it to be managed effectively. Just not make itself.
fusiongyro 9y ago
For #2, you can mark intermediates worth keeping with .PRECIOUS. https://www.gnu.org/software/make/manual/html_node/Special-Targets.html https://www.gnu.org/software/make/manual/html_node/Special-T... For #3, I think you may be misreading ps; on Linux, ps will show you threads as if they are processes when they are not.
- mnw21cam 9y ago
  For #2, .PRECIOUS doesn't help me. From the make manual: "Also, if the target is an intermediate file, it will not be deleted after it is no longer needed, as is normally done." This means that my intermediate files will never be deleted by make, even when everything that is built from them has been completed. For #3, no I think I know how to read ps. I don't want 64 64-thread processes running on my 64-thread server, because that is hell for an OS scheduler, and makes things run slower, not faster.
  - fusiongyro 9y ago
    For #2, you could always make a dependency that removes your intermediates for you after your final use. You can't be mad at make because it deletes intermediates and because it doesn't delete intermediates. Make isn't psychic. For #3, I didn't mean to come across as pedantic. I haven't encountered what you're describing, but I have personally been surprised by how Linux does process accounting, so I apologize; I just figured you were being bitten by the same thing. I like make a lot, but I don't use it for everything, because sometimes there simply are better tools for the task, and I hope you were able to figure out a solution.
xelxebar 9y ago
1. Oh. I screwed up. Thanks for the correction. Apparently, I'm the one that needs to read the info page again! :P 2. This is an interesting case. It's like the opposite of .DELETE_ON_ERROR. Anyway, it seems like you have some legitimate workloads that make just doesn't fit well with. Mind sharing the solution you designed?
- mnw21cam 9y ago
  Eventually. Got a lot on my plate at the moment.

chubot 9y ago

I agree with all your criticisms, except I'm a bit confused about #3. Are you saying you're using Make with multi-threaded build actions? As far as I know, most compilers are single-threaded, so this isn't much of an issue in practice. But I'm curious where you've encountered this problem.

mnw21cam 9y ago
No, I was using make to process large files for bioinformatics. So, think 60GB (compressed) of sequencing data from a whole genome sequencing run, which comes as a set of ~800,000,000 individually sequenced short stretches of DNA in two files. A multi-threaded process converts that into a file containing the sequences and where they align in the human genome, and takes about a day. Once that job has been finished, other jobs can be kicked off to use the produced data. Overall, the build process is a DAG with several hundred individual jobs, and performing that in a make-like system helps it to be managed effectively. Just not make itself.

fusiongyro 9y ago

For #2, you can mark intermediates worth keeping with .PRECIOUS. https://www.gnu.org/software/make/manual/html_node/Special-Targets.html https://www.gnu.org/software/make/manual/html_node/Special-T... For #3, I think you may be misreading ps; on Linux, ps will show you threads as if they are processes when they are not.

mnw21cam 9y ago
For #2, .PRECIOUS doesn't help me. From the make manual: "Also, if the target is an intermediate file, it will not be deleted after it is no longer needed, as is normally done." This means that my intermediate files will never be deleted by make, even when everything that is built from them has been completed. For #3, no I think I know how to read ps. I don't want 64 64-thread processes running on my 64-thread server, because that is hell for an OS scheduler, and makes things run slower, not faster.
- fusiongyro 9y ago
  For #2, you could always make a dependency that removes your intermediates for you after your final use. You can't be mad at make because it deletes intermediates and because it doesn't delete intermediates. Make isn't psychic. For #3, I didn't mean to come across as pedantic. I haven't encountered what you're describing, but I have personally been surprised by how Linux does process accounting, so I apologize; I just figured you were being bitten by the same thing. I like make a lot, but I don't use it for everything, because sometimes there simply are better tools for the task, and I hope you were able to figure out a solution.

xelxebar 9y ago

1. Oh. I screwed up. Thanks for the correction. Apparently, I'm the one that needs to read the info page again! :P 2. This is an interesting case. It's like the opposite of .DELETE_ON_ERROR. Anyway, it seems like you have some legitimate workloads that make just doesn't fit well with. Mind sharing the solution you designed?

mnw21cam 9y ago
Eventually. Got a lot on my plate at the moment.