Re: portfs and port_send_event

From: Frits Hoogland <>
Date: Sat, 14 Apr 2018 16:51:31 +0200
Message-Id: <>

I am not familiar with these functions.
It seems this port event framework is a solaris only thing, used as a substitute for semaphores, obviously because oracle thinks they have better performance or scale better. (actually they seem to say it’s mostly a substitute for polling event completion). There are multiple blogposts explaining them, telling essentially that.

What is it that you need to know?
port_send_event seems to send something, the address is probably a pointer to a struct, and I am quite sure a foreground that has committed is the receiver of it, because that is what the function of sskgpwpost does. So that would be equivalent of semop on linux, posting the semaphore on which a foreground is sleeping, waiting for the logwriter to get notified the redo write has finished.

I don’t know the port event framework, but if you look at what happens when multiple processes need posting on a semaphore on linux, another function (sskgpwvectorpost) is executed and still all processes are posted serially, maybe the event framework can post them all at once. Again, I don’t know the port event framework, this might not be true, but this is the one of the problems that the port event framework is documented to solve.

And the database implemented a solution for this already, which is “polling mode”, which doesn’t require any communication from the logwriter to a waiting foreground after writing, because the foreground checks writing progress itself.

Frits Hoogland <> <> Mobile: +31 6 14180860

> On 12 Apr 2018, at 10:39, Noveljic Nenad <> wrote:
> Is somebody familiar with the specification of Oracle Solaris kernel functions portfs and port_send_event?
> These functions are a part of the Solaris Event Completion framework. This framework seems to be used instead of semaphores for posting messages between processes on the Solaris implementation of Oracle.
> Here is an example of a call stack within the lgwr process:
> port_send_event(FFFFA22B765EFBA8)
> oracle`sskgpwpost+0xf0
> oracle`kslpsprns+0x19c
> oracle`kcrfw_slave_queue_insert+0x361
> oracle`kcrfw_redo_write_driver+0x73e
> oracle`ksbabs+0x15c4
> oracle`ksbrdp+0x4ce
> oracle`opirip+0x2cd
> oracle`opidrv+0x24a
> oracle`sou2o+0x64
> oracle`opimai_real+0x9f
> oracle`ssthrdmain+0x21d
> oracle`main+0x94
> oracle`0xabcb95b
> While the other port_* functions are well documented (see <> ) these two are completely missing despite being heavily used.
> Best regards,
> Nenad
> <>
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Received on Sat Apr 14 2018 - 16:51:31 CEST

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