From: Mark Hills <mark-UrrBsZIrrsb10XsdtD+oqA@public.gmane.org>
To: Kent Overstreet
<kent.overstreet-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
Cc: linux-bcache-u79uwXL29TY76Z2rM5mHXA@public.gmane.org
Subject: Re: First observations with bcache
Date: Fri, 23 Sep 2011 00:14:07 +0100 (BST) [thread overview]
Message-ID: <1109221154170.28261@jrf.vwaro.pbz> (raw)
In-Reply-To: <20110922061339.GA14669@moria>
On Wed, 21 Sep 2011, Kent Overstreet wrote:
> Ok, I should have all the issues you found fixed. They're only compile
> tested but they should be correct - tomorrow I'll pull them into the dev
> branch and test them.
You mean commit a1f7b3d? I checked this out quickly now, but on install
got:
DEPMOD 3.1.0-rc7-bcache+
WARNING: Loop detected: /lib/modules/3.1.0-rc7-bcache+/kernel/block/bcache.ko needs bcache_util.ko which needs bcache.ko again!
WARNING: Module /lib/modules/3.1.0-rc7-bcache+/kernel/block/bcache.ko ignored, due to loop
WARNING: Module /lib/modules/3.1.0-rc7-bcache+/kernel/block/bcache_util.ko ignored, due to loop
Perhaps I will look in more detail tomorrow.
Did you make any steps in removing -std=gnu99? I think this is a must; I
could not see this trend elsewhere in the existing kernel code.
> But I got that and the most recent stable code pushed to the public
> repository. I got rid of the 2.6.34 branch, the bcache branch is now
> based off 3.1.
>
> You got it up and running? How's it working?
Hi, yes I did get it running before. The effect of the caching in tests
was as I'd hoped; it felt like it was working well.
Something I found particularly interesting is the pass-through for
sequential operations. With an SSD an order of magnitude faster than HDD,
it seems like an interesting part of the project could be in the
heuristics for this.
But I haven't been using it as I'd hoped, because of re-formatting the
source device. IMO this is an unnecessary barrier to adoption. Flashcache,
dm-cache etc. show a simple design that doesn't require this.
Whilst the aims of auto-configuration, thin provisioning, tiering etc. are
admirable, it feels rather ambitious.
I mentioned on IRC the other week: I'd like to see bcache focus on the
cache. From a user perspective, it already has a major contribution in
this area, and could slot in neatly to provide this -- such as within
device-mapper.
It would also have a clear position in the existing structure, which would
ease the review process and leave the focus on the code quality and docs.
Thanks
--
Mark
prev parent reply other threads:[~2011-09-22 23:14 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-09-10 13:44 First observations with bcache Mark Hills
[not found] ` <1109101110320.2733-4jfXtw+jRJ582hYKe6nXyg@public.gmane.org>
2011-09-10 13:45 ` [PATCH 1/7] Use exported call to up/down read Mark Hills
[not found] ` <1315662339-3115-1-git-send-email-mark-UrrBsZIrrsb10XsdtD+oqA@public.gmane.org>
2011-09-10 13:45 ` [PATCH 2/7] Provide 64-bit arithmetic functions Mark Hills
2011-09-10 13:45 ` [PATCH 3/7] Break fuzz test to allow building as module Mark Hills
2011-09-10 13:45 ` [PATCH 4/7] Don't require linkage against closure_lock Mark Hills
2011-09-10 13:45 ` [PATCH 5/7] Allow closure debugging without CONFIG_DEBUG_FS Mark Hills
2011-09-10 13:45 ` [PATCH 6/7] Temporary fix to pr_latency() Mark Hills
2011-09-10 13:45 ` [PATCH 7/7] Don't require latency_warn_ms from bcache_util.o Mark Hills
2011-09-10 21:39 ` [PATCH 1/7] Use exported call to up/down read Kent Overstreet
2011-09-22 6:13 ` First observations with bcache Kent Overstreet
2011-09-22 23:14 ` Mark Hills [this message]
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