|From:||Andi Kleen <email@example.com>|
|Subject:||Add a sysconf syscall|
|Date:||Fri, 13 May 2011 16:24:14 -0700|
We ran into some problems with programs querying then number of processors at startup through sysconf. This calls into /proc from glibc, which is quite slow and scales poorly if the program is frequently executed. This happens with programs using Sleepycat DB for example. While there are worarounds -- like using sched_getaffinity -- they don't have quite equivalent semantics. This patchkit adds a sysconf() syscall to the kernel that allows to get this information much faster. It only implements a subset of sysconf() -- all the information the kernel knows usefully about. Another advantage is that the kernel can in several cases offer more accurate information than glibc, which has to guess. The syscall is quite compat and not a significant burden. In addition I did a few cleanups first to export all the information needed by sysconf clearly from other subsystems. -Andi -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to firstname.lastname@example.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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