Re: Syslets, Threadlets, generic AIO support, v6

From: Jens Axboe
Date: Wed May 30 2007 - 03:41:30 EST


On Tue, May 29 2007, Zach Brown wrote:

Thanks for picking this up, Zach!

> - cfq gets confused, share io_context amongst threads?

Yeah, it'll confuse CFQ a lot actually. The threads either need to share
an io context (clean approach, however will introduce locking for things
that were previously lockless), or CFQ needs to get better support for
cooperating processes. The problem is that CFQ will wait for a dependent
IO for a given process, which may arrive from a totally unrelated
process.

For the fio testing, we can make some improvements there. Right now you
don't get any concurrency of the io requests if you set eg iodepth=32,
as the 32 requests will be submitted as a linked chain of atoms. For io
saturation, that's not really what you want.

I'll take a stab at improving both of the above.

--
Jens Axboe

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