Messages in this thread | | | Date | Wed, 19 Sep 2001 16:49:30 -0500 | From | "Christopher K. St. John" <> | Subject | Re: [PATCH] /dev/epoll update ... |
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Davide Libenzi wrote: > > > - check new_socket_fd for readable, writable, and > > error. if any true, then add new event to > > event queue, as if the state had changed. > > No it does't check. It's not needed for how it works. >
Yes, I see that it currently works that way. I'm suggesting that it's a needlessly awkward way to work. It also results in thousands of spurious syscalls a second as servers are forced to double check there isn't i/o to be done.
This is frustrating, as the application must ask for information that the kernel could have easily provided in the first place.
Providing an initial set of events makes application programming easier, doesn't appear to add significant complexity to the driver (maybe), greatly reduces the number of required system calls, and still fits neatly into the conceptual api model. It seems like a clear win.
> I intentionally changed the name to epoll because it > works in a different way. >
Am I missing something? I don't think you'd need a linear scan of anything, and there wouldn't be any changes to the api. Existing code would work exactly the same. Etc.
It's Davide's patch, and if he doesn't like my suggestion, I certainly don't expect him to change his code. If there's any consensus that the "initial event set" behavior is a good thing, I'd be willing to whip up a patch to Davide's patch. OTOH, if there's a good reason the changes are a bad thing, I don't want to confuse the issue with yet-another /dev/poll variant.
Does anybody else have an opinion?
-- Christopher St. John cks@distributopia.com DistribuTopia http://www.distributopia.com - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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