Mailinglist Archive: opensuse-factory (1029 mails)

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Re: [opensuse-factory] journalctl very slow
On Tue, Nov 5, 2013 at 8:15 PM, Ruediger Meier <sweet_f_a@xxxxxx> wrote:
On Sunday 03 November 2013, Claudio Freire wrote:
On Sun, Nov 3, 2013 at 3:42 PM, Claudio Freire
<klaussfreire@xxxxxxxxx> wrote:
I suggest monitorion I/O with iostat to see what the issue is.
There should be a lot of read-request-merges since watching a
journal log should be sequential access. If read-request-merges are
low and avg request sizes too, then it's probably fragmentation.

I'll be happy to provide a few patches for you to try trying to
address that, if you're willing to rebuild and test.

Or better yet. Send me the journal file somehow?

That way I can test myself.

Thanks a lot for your efforts but unfortunately I had removed that
useless journal stuff already.
Actually I also don't really believe that you could accelerate it by
factor 1000 to make it at least a bit more useful. Maybe it's this
hopeless looking situation why upstream does not "want" to fix that,
instead telling us that our needs or hardware is wrong.

Well, without knowing what the bottleneck is, it's hard to tell. My
money was either I/O slowness due to fragmentation (easy to fix with a
posix_fallocate call) or repeated decompression overhead (fixed not so
easily but still easy-ish with a block cache). With a patch that
addresses the bottleneck, I bet upstream would pay attention.
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