I am using kubuntu 10.10 with a 4 cores cpu. When I use 'make -j2' to build a cpp project, 2 core's cup usage become 100%, desktop environment become no response, and build procedure make no progress.
Version info:
The GNU make's version is 3.81
gcc version 4.4.5 (Ubuntu/Linaro 4.4.4-14ubuntu5)
How to resolve this problem? Thanks.
There's not really enough information here to give you a definitive answer. First it's not clear if this happens only when you run with -j2. What if you run without parallelism (no -j)? When you say "2 core's CPU usage [goes to] 100%", what is happening on those CPUs? If you run "top" in another terminal and then start your build, what is showing in top?
Alternatively, if you run "make -d -j2" what program(s) is make running right before the CPU goes to 100%?
The fact that the desktop is unresponsive as well hints at some other problem, rather than CPU usage, since you have 4 cores and only 2 are busy. Maybe something is chewing up all your RAM? Does the system come back after a while (indicating that the OOM killer got involved and stomped something)?
If none of that helps, you can run make under strace, something like "strace -f make -j2" and see if you can figure out what is going on. This will generate a metric ton or two of output but if, when the CPU is pegged, you see something running over and over and over you might get a hint.
Basically I can see these possibilities:
It's not make at all, but rather whatever command make is running that's just bringing your system down. You imply it's just compiling C++ code so that seems unlikely unless there's a bug somewhere.
Make is recursing infinitely. Make will rebuild its own makefile, plus any included makefile, then re-exec itself. If you are not a bit careful defining rules for rebuilding included makefiles make can decide they're always out of date and rebuild/rexec forever.
Something else
Hopefully the above hints will set you on a path to discovering what's going on.
Are you sure the project is prepared for parallel compilation? Maybe the prerequisites aren't correctly ordered.
If you build the project with just "make" the compilation finish? If it gets to the end is a target dependency problem.
Related
Since some years ago I started using Qt in both Windows 7 as well as in Linux Ubuntu and it would always compile fast with MinGW being used for Windows. But in the last couple of years or so, maybe thanks to updates in the version of both Qt and MinGW, I started detecting a slow down in the compiling speed inside Windows. I did some research trying to find why MinGW had started to become so slow compared to Linux (it wasn't before!) and everything people told me was that MinGW was slower in Windows and that it would be better, if possible, to just use Linux.
Since I wanted to continue my project, I followed the suggestion and since I've being using Linux with relatively no problems. The situation now is that I must go back to Windows (now updated to Windows 10) to make visual corrections for this OS and I need to once again work with MinGW having to face the same problem as before.
But for some reason it seems that the slowness of MinGW became even worse! While before I at least was able to compile the app in around 4 minutes, now the last time I tried it took 38 minutes before I gave up and went to sleep - and this is for a project that takes only 1:03 minute to be compiled in Linux [under the same compile configuration]!
Well I'm still aware about the slowness of MinGW, but as a quick research around this problem on the web reveals, that is just too slow: all backtesting one can find in other threads here on SO reveals at best 2x-3x more time to compile a project, not 38x+!!
So I would like to know what kind of possible problems I might have in my Windows for this exaggerated slowness to happen. I know I ended up installing at least 4 different versions of MinGW; could this have brought the problem?
It's interesting also to notice that when compiling using the -j option and watching the Compile Output log in Qt Creator alongside Process Explorer, there are moments when the compiling simple pauses for 10 seconds or more and the CPU usage drops from its ~100% to close to 5% with nothing happening till it suddenly continues the compilation process. I'm sure this constant pauses are part of the above average time, but I have no idea why MinGW is showing this behaviour.
You might want to check where the time is spent.
There a lot of tools that allow you to capture what a certain process is doing, I name just two of them:
ProcMon
XPerf or its successor
But to analyze the reports generated by these tools you need a rather deep understanding. If this doesn't help temporarily disable other running services and program step-by-step (if you want to know which program causes the problem) or disable all of them at once.
Looking at the spikes of cpu usage that TaskManager or Procexp by sysinternals show might help too to identify those components that block your cpu.
If your antivirus is the cause of the collision that makes the compile so slow you can define exceptions, then the antivirus will not scan certain programs or paths.
So perhaps it is easier to first try the compilation process with a disabled antivirus software or even from a clean live boot Windows CD.
I have a GCC 3.4.3 toolchain built for ARM (arm-elf) here in my Windows 7 (64bits) setup. We use this to build our software product to a specific hardware.
Recently, we have been experiencing some problems with this particular toolchain.
First, when we try to call arm-elf-gcc to build each source file (there are lots of them), it complained about it not being able to allocate enough heap.
Then, I thought it was some problem with the outdated cygwin DLL distributed by the hardware vendor. So I replaced it with a more recent version (1.7.35). The problem stopped and the build does go ok but now it is incredibly SLOW (it took about 40s to build a single .c source file).
Does anyone has experienced this problem before? How can I debug and fix it?
Thanks in advance.
Sounds like you have had a similar problem to me and might be worth trying this. When i first encountered this, I had to install cygserver and then run this (make sure you right click admin):
Previous solution
However, the problem resumed and I simultaneously couldn't install/uninstall some problems. Eventually I resolved this by terminating SearchIndexer.exe in Task Manager. Indeed, I have gone in to Control Panel / Searach Indexing and pulled it back from doing any indexing. My installation taking 1hr took 3 more seconds. The change to Cygwin was instantaneous.
Cygwin is now flying!
I've had an issue with slow execution of builds for a while on cygwin, using make and a proprietary compiler that "isn't gcc, honest...", but has very similar error returns.
I was forced to update yesterday and ran into the issue of rebaseall simply failing to execute. This forced me to dig into other things and I found a report that Trusteer Rapport/End Point Protection has been known to cause issues with rebaseall,and slow response times. So I removed it. This fixed the rebaseall, but has also massively increased the speed of my build. Worth checking to see if you have it installed, try removing it. AV packages in general are reputed to interfere and may be the cause.
I was compiling Qt5 for a embedded device on the device itself. This takes a long time since Qt sources are about 800mb and the embedded device isn't exactly fast.
Everything was running well, until a power shortage prevented the device from finishing make, therefore halting the compilation process.
Is there any way to resume from where it was left of?
If it's a well-formed makefile, simply re-running make should allow you to resume the process.
The make -t command mentioned (assuming gnu make) simply touches the files (updates the timestamps) and doesn't actually perform the actions in the makefile so at this point, you'll probably have to start over.
Also rather than building on the slow target, consider setting up a cross-compiler and build system. It's often a lot of work initially, but pays considerable dividends over time. I would recommend crosstool-ng as one of the least painful ways of setting up such an environment.
After some pain and suffering, i managed to install everything necessary for MinGW to work on a computer not on the network.
It worked nicely for a couple days, but now I'm experiencing very long delays before anything starts to happen after i give the "make" command to build my project.
I tried disabling the network, as suggested here: Why is MinGW very slow?
But it didn't help.
Note that it's not the actual compilation / linking progress that is slow, but the startup of those processes seems to take forever. 5-10 minutes. Except if i just did it, then it starts in 10-30 seconds.
I know, it used to take a lot longer to load those tapes on Commodore, but over the years I have grown impatient.
Any ideas?
Try doing make -r (without implicit rules). For me it was a difference between 30 seconds and fraction of a second for single cpp file.
Explanation:
I've had the same problem MinGW make long ago. I've used make -d to investigate. It was then obvious that make uses a gazillion of implicit rules for every dependency file - if my file had dep on shared_ptr.hpp then make checked for shared_ptr.hpp(o|c|cc|v|f|r|.. and dozens other combinations). Of course those files didn't exist. It looks like checking for file mod time/existence (when it doesn't really exist) on Windows platform is a lot slower than on Linux (becouse with Linux i didn't see any difference with/without -r switch).
I am working on a project using Google's cmockery unit testing framework. For a while, I was able to build the cmockery project with no problems. e.g. "./configure", "make && make install" etc. and it took a reasonable amount of time (1-2 minutes or so.) After working on other miscellaneous tasks on the computer and going back to re-build it, it becomes horrendously slow. (e.g. after fifteen minutes it is still checking system variables.)
I did a system restore to earlier in the day and it goes back to working properly for a time. I have been very careful about monitoring any changes I make to the system, and have not been able to find any direct correlation between something I am changing and the problem. However, the problem inevitably recurs (usually as soon as I assume I must have accidentally avoided the problem and move on). The only way I am able to fix it is to do a system restore to a time when it was working. (Sometimes restarting the machine works as well, sometimes it does not.)
I imagine that the problem is between the environment and autoconf itself rather than something specific in cmockery's configuration. Any ideas?
I am using MinGW and under Windows 7 Professional
Make sure that antivirus software is not interfering. Often, antivirus programs monitor every file access; autoconf accesses many files during its operation and is likely to be slowed down drastically.