From: Christoph Hellwig <hch@infradead.org>
To: Benjamin ESTRABAUD <be@mpstor.com>
Cc: "J. Bruce Fields" <bfields@fieldses.org>,
"linux-nfs@vger.kernel.org" <linux-nfs@vger.kernel.org>,
"bc@mpstor.com" <bc@mpstor.com>,
Christoph Hellwig <hch@infradead.org>
Subject: Re: Issue running buffered writes to a pNFS (NFS 4.1 backed by SAN) filesystem.
Date: Mon, 25 May 2015 08:13:10 -0700 [thread overview]
Message-ID: <20150525151310.GA18386@infradead.org> (raw)
In-Reply-To: <555CD2F0.6080408@mpstor.com>
On Wed, May 20, 2015 at 07:31:12PM +0100, Benjamin ESTRABAUD wrote:
> After 25 iterations (after creating a 25GiB file, for a cumulative total of
> 325GiB if including the testfile.1G -> testfile.24G) the issue occured
> again. The IO rate to the SAN LUN dropped severely to a real 3MiB/sec
> (measured at the SAN LUN block device level).
>
> Also I've noticed that a kernel process is taking up 100% of one core at
> least:
>
> 516 root 20 0 0 0 0 R 100.0 0.0 11:09.72
> kworker/u49:4
Can you send me the output of "perf record -ag" for that run?
Also can you send the output from trace-cmd for tracing all nfsd.layout*
tracepoints for such a run?
> Would the 25GiB figure ring any bells to you? Would there be a way for me to
> identify this workqueue (figure out if it is pNFS related)?
Perf record should help by looking at the cycles spent.
next prev parent reply other threads:[~2015-05-25 15:13 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-05-15 17:44 Issue running buffered writes to a pNFS (NFS 4.1 backed by SAN) filesystem Benjamin ESTRABAUD
2015-05-15 19:20 ` J. Bruce Fields
2015-05-20 16:27 ` Benjamin ESTRABAUD
2015-05-20 18:31 ` Benjamin ESTRABAUD
2015-05-25 15:13 ` Christoph Hellwig [this message]
2015-05-26 16:43 ` Benjamin ESTRABAUD
2015-05-20 19:40 ` J. Bruce Fields
2015-05-21 10:09 ` Benjamin ESTRABAUD
2015-05-17 16:38 ` Christoph Hellwig
2015-05-20 16:30 ` Benjamin ESTRABAUD
2015-05-25 15:14 ` Christoph Hellwig
2015-05-26 16:44 ` Benjamin ESTRABAUD
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