Fix runtime crash when parsing /proc/cpuinfo fails #1900
Conversation
The testcase fails on sparc64, because the parsing of /proc/cpuinfo fails and thus currently returns "0" CPUs which finally leads to division-by-zero faults in the tests. Fix the issue by returning at least "1" CPU which allows the tests to run. A error message will be printed in any case. Long-term the code should be fixed to parse the cpuinfo output on sparch which looks like this: ... type : sun4v ncpus probed : 48 ncpus active : 48
|
A failing log on a sparc64 machine can be found here: Currently I suggest to apply this trivial patch as-is to get rid of the problem for now. In the long run I see two options: I suggest to implement b). |
| @@ -561,10 +561,12 @@ int GetNumCPUsImpl() { | |||
| } | |||
|
|
|||
| int GetNumCPUs() { | |||
| const int num_cpus = GetNumCPUsImpl(); | |||
| int num_cpus = GetNumCPUsImpl(); | |||
| if (num_cpus < 1) { | |||
| std::cerr << "Unable to extract number of CPUs. If your platform uses " | |||
There was a problem hiding this comment.
should this instead be an assert that would require platform support to be added?
There was a problem hiding this comment.
I generally don't like an asserts, unless there is a really CRITICAL problem.
Not being able to correctly detect the number of CPUs is not at all a critical problem.
Currently it prints that the number of CPUs could not be determined at that someone may take a look at it.
With my addition it will then will return 1 CPU (which is of course somewhat true since we wouldn't be here if there was no CPU, although maybe not the perfect answer).
(... or even better use sysconf(_SC_NPROCESSORS_ONLN) in an upcoming patch.)
The testcase fails on sparc64, because the parsing of /proc/cpuinfo fails and thus currently returns "0" CPUs which finally leads to division-by-zero faults in the tests.
Fix the issue by returning at least "1" CPU which allows the tests to run. A error message will be printed in any case.
Long-term the code should be fixed to parse the cpuinfo output on sparch which looks like this:
...
type : sun4v
ncpus probed : 48
ncpus active : 48