need better POSIX semaphore support
amdmi3 at amdmi3.ru
Sun May 30 14:30:39 UTC 2010
Not long ago, POSIX semaphores support was enabled by default as it's
becoming more widely used, by e.g. firefox. However, the support
for these is still incomplete: we only have systemwide limit of 30
semaphores, and that doesn't seem to be configurable neither online with
sysctl, nor at boottime from loader.conf. I only was able to raise
semaphore count by changing SEM_MAX in kernel sources.
The real appliaction which needs more semaphores is lightspark
(graphics/lightspark-devel) flash plugin - it uses ~40 sems for simple
clips and ~250 for something like youtube videos.
Until there more apps that require proper semaphore support, I guess
we need to improve it asap. Given the amount of memory used by ksem,
the least can be done is SEM_MAX bumped up to 5120 or so for
non-embedded kernels. 5120 semaphores require just 644k of kernel
memory (judging by vmstat), and is "ought to be enough for anybody".
Another good thing would be to make it configurable at boot-time
or even better in runtime.
Dmitry Marakasov . 55B5 0596 FF1E 8D84 5F56 9510 D35A 80DD F9D2 F77D
amdmi3 at amdmi3.ru ..: jabber: amdmi3 at jabber.ru http://www.amdmi3.ru
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