Re: [PATCH V8 00/33] loop: Issue O_DIRECT aio using bio_vec

[Maxim Patlasov]

07/31/2013 01:28 AM, Andrew Morton ÐÐÑÐÑ:
> On Thu, 25 Jul 2013 12:50:26 -0500 Dave Kleikamp <dave.kleikamp@xxxxxxxxxx> wrote:
>
> > This patch series adds a kernel interface to fs/aio.c so that kernel code can
> > issue concurrent asynchronous IO to file systems.  It adds an aio command and
> > file system methods which specify io memory with pages instead of userspace
> > addresses.
> >
> > This series was written to reduce the current overhead loop imposes by
> > performing synchronus buffered file system IO from a kernel thread.  These
> > patches turn loop into a light weight layer that translates bios into iocbs.
> Do you have any performance numbers?
>
> Does anyone care much about loop performance?  What's the value here?

OpenVZ uses loopback-device to keep per-container filesystems. We care 
much about overhead introduced by loop: IO-bound applications run on top 
of per-container filesystem shouldn't perform worse than on top of host 
filesystem. So the value for us is zero overhead.

Thanks,
Maxim
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/