Re: POSIX message queues

[Peter Waechtler]

On Sunday, October 05, 2003, at 08:32PM, Jakub Jelinek <jakub@xxxxxxxxxx> wrote:

>> Speaking of librt - I should not have to link in pthreads and the
>> run-time overhead associated with it (locking stdio etc.) just so I
>> can use shm_open().  Any chance of fixing this?
>
>That overhead is mostly gone in current glibcs (when using NPTL):
>a) e.g. locking is done unconditionally even when libpthread is not present
>   (it is just lock cmpxchgl, inlined)


a "lock cmpxchg" is > 100 cycles (according to a recent Linux Journal article
from Paul McKenney: 107ns on 700MHz PentiumIII)

But I think you will have benchmarked the alternatives?
BTW, what are they?

you suggested naming the syscall number symbols NR_mq_open instead of
NR_sys_mq_open. In the stub I want to overload some syscalls (e.g. mq_open)
but others not (e.g. mq_timedsend).

How to deal with that?

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