On Feb 23, 2007, at 8:31 AM, John Buckman wrote:
Should also get around to implementing ns_mutex eval $mutex
$script--acquire the mutex, evaluate the script, release the mutex.
Catch any Tcl errors and re-throw them. This guarantees that the
mutex
is unlocked, which avoids the trivial
Dossy,
The problem described is exactly what ns_cond solves. But what is the problem?
Executing code withing a mutex lock which takes meaningful time.
Instead with ns_cond, you use a mutex just so you can grab a condition
variable, or at least try to grab it, and if not go to sleep and wait.
So, the question becomes: is it better to add -timeout time to
all the
blocking subcommands, or to add ns_mutex trylock? In theory,
-timeout 0 should perform the trylock equivalent.
I'd vote for -timeout on all lock requests, as that way I get both
the see if lock is available
That is how the ns_cache stuff works in 4.5. There is a maxwait flag
that can be set when the cache is created. If one thread has the
lock (updating the cache) the others will only wait a certain amount
of time before timing out - good deadlock prevention.
M
On Feb 23, 2007, at 10:06
I'm looking to have mutexes with timeouts, and I see support in the C
code for this but none carried over to Tcl.
In the C code, there's a Ns_MutexTryLock() function, but no tcl
function for calling it.
Ns_MutexLock calls Ns_MutexTryLock() and there appears to be timeout
support:
if
I have some example code of condition wait:
http://rmadilo.com/m2/servers/rmadilo/modules/tcl/twt/packages/db/tcl/datasource-procs.tcl
The procs lock, unlock, wait, popPool, etc. Wrap the ideas up pretty easily,
but the question is what happens when you code times out waiting for a
resource?
Forgot to mention that I know about Dossy's comment in the wiki that
nsv_incr can be used to this effect, and I'm doing that.
http://panoptic.com/wiki/aolserver/Nsv_incr
but I was wondering why try wasn't part of ns_mutex when the C code
is there for it.
-john
On Feb 22, 2007, at 3:09
Just curious, but what's the use case where you would use something like
this?
- n
On 2/22/07, Tom Jackson [EMAIL PROTECTED] wrote:
I have some example code of condition wait:
http://rmadilo.com/m2/servers/rmadilo/modules/tcl/twt/packages/db/tcl/datasource-procs.tcl
The procs lock, unlock,
