Re: shallow thoughts on SHM

2019-10-28 Thread Richard Laager via devel
On 10/28/19 3:37 PM, Hal Murray wrote: > >> Are multiple readers a thing? What's the use case here? I mean, presumably >> I'm not running multiple ntpds on the same system, right? > > The idea is to be able to run shmmon without stopping ntpd. That makes sense. Thanks! > The other half of maki

Re: shallow thoughts on SHM

2019-10-28 Thread Hal Murray via devel
> Are multiple readers a thing? What's the use case here? I mean, presumably > I'm not running multiple ntpds on the same system, right? The idea is to be able to run shmmon without stopping ntpd. The other half of making the read side of SHM read only is that is cleans up the file protection

Re: shallow thoughts on SHM

2019-10-28 Thread Richard Laager via devel
On 10/26/19 10:24 PM, Hal Murray via devel wrote: > That approach is worth investigating, but it adds a layer of complexity if > you > want to support more than a single reader. Are multiple readers a thing? What's the use case here? I mean, presumably I'm not running multiple ntpds on the same s

Re: shallow thoughts on SHM

2019-10-27 Thread James Browning via devel
On Sat, Oct 26, 2019, at 8:24 PM Hal Murray wrote: > > > I do not have access to a copy of POSIX and the SuSv2 seems to have SHM > > support. > > You can probably get what you need from man pages. Try man shm_overview There are links in the documentation that I should have read before removing

Re: shallow thoughts on SHM

2019-10-26 Thread Hal Murray via devel
> I do not have access to a copy of POSIX and the SuSv2 seems to have SHM > support. You can probably get what you need from man pages. Try man shm_overview System V shared memory (shmget(2), shmop(2), etc.) is an older shared memory API. POSIX shared memory provides a s

Re: shallow thoughts on SHM

2019-10-26 Thread James Browning via devel
On Sat, Oct 26, 2019 at 7:49 AM Eric S. Raymond wrote: > James Browning via devel : > > I would like to propose a new SHM implementation > > The trouble with any new SHM proposal is that the underlayer is not > POSIX and we theefore can't count on it continuing to exist. > > We need that kind of

Re: shallow thoughts on SHM

2019-10-26 Thread Eric S. Raymond via devel
James Browning via devel : > I would like to propose a new SHM implementation The trouble with any new SHM proposal is that the underlayer is not POSIX and we theefore can't count on it continuing to exist. We need that kind of funcrionality, but any new design should be dome over an IPC layer th

shallow thoughts on SHM

2019-10-26 Thread James Browning via devel
The length of the SHM construct appears to date back to 1997 at that time according to Wikipedia only four processor architectures had 64-bit address spaces. I have no information on the prevalence of 64-bit processors. However, I think it is reasonable to assume that the integers of that time defa