6.0 on Dell 1850 with PERC4e/DC RAID?
Scott Mitchell
scott+lists.freebsd at fishballoon.org
Fri Jan 6 02:55:15 PST 2006
On Fri, Jan 06, 2006 at 01:21:56PM +1100, Michael Vince wrote:
> FYI there also has been a big update to the amr driver which claims to
> dramatically increase performance among other things, interestingly
> enought it was augmented by Yahoo, I can only assume they are moving to
> Dell, yahoo for me (and now you :).
> The updates are still in -current but it will be MFC'ed into stable
> sooner or later.
>
> http://lists.freebsd.org/pipermail/cvs-src/2005-December/056814.html
Yeah, I saw that, and it sounds most excellent. Good to see some real
support from the likes of Dell and LSI, too.
I might be able to get away with running -stable on this machine, but
-current will be right out. Hopefully these changes can be MFCed in time
for 6.1.
Scott
> Log:
> Mega update to the LSI MegaRAID driver:
>
> 1. Implement a large set of ioctl shims so that the Linux management apps
> from LSI will work. This includes infrastructure to support adding,
> deleting
> and rescanning arrays at runtime. This is based on work from Doug
> Ambrosko,
> heavily augmented by LSI and Yahoo.
>
> 2. Implement full 64-bit DMA support. Systems with more than 4GB of RAM
> can now operate without the cost of bounce buffers. Cards that cannot do
> 64-bit DMA will automatically revert to using bounce buffers. This option
> can be forced off by setting the 'hw.amr.force_sg32" tunable in the loader.
> It should only be turned off for debugging purposes. This work was
> sponsored
> by Yahoo.
>
> 3. Streamline the command delivery and interrupt handler paths after
> much discussion with Dell and LSI. The logic now closely matches the
> intended design, making it both more robust and much faster. Certain
> i/o failures under heavy load should be fixed with this.
>
> 4. Optimize the locking. In the interrupt handler, the card can be
> checked
> for completed commands without any locks held, due to the handler being
> implicitely serialized and there being no need to look at any shared data.
> Only grab the lock to return the command structure to the free pool. A
> small optimization can still be made to collect all of the completions
> together and then free them together under a single lock.
>
> Items 3 and 4 significantly increase the performance of the driver. On an
> LSI 320-2X card, transactions per second went from 13,000 to 31,000 in my
> testing with these changes. However, these changes are still fairly
> experimental and shouldn't be merged to 6.x until there is more testing.
>
> Thanks to Doug Ambrosko, LSI, Dell, and Yahoo for contributing towards
> this.
>
>
>
>
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