From: Duncan <1i5t5.duncan@cox.net>
To: linux-btrfs@vger.kernel.org
Subject: Re: NVMe SSD + compression - benchmarking
Date: Sun, 29 Apr 2018 08:28:09 +0000 (UTC) [thread overview]
Message-ID: <pan$4c272$fabeda98$48538e85$39262988@cox.net> (raw)
In-Reply-To: 6adcb5da-16af-5453-383b-f289e9857506@swiftspirit.co.za
Brendan Hide posted on Sat, 28 Apr 2018 09:30:30 +0200 as excerpted:
> My real worry is that I'm currently reading at 2.79GB/s (see result
> above and below) without compression when my hardware *should* limit it
> to 2.0GB/s. This tells me either `sync` is not working or my benchmark
> method is flawed.
No answer but a couple additional questions/suggestions:
* Tarfile: Just to be sure, you're using an uncompressed tarfile, not a
(compressed tarfile) tgz/tbz2/etc, correct?
* How does hdparm -t and -T compare? That's read-only and bypasses the
filesystem, so it should at least give you something to compare the 2.79
GB/s to, both from-raw-device (-t) and cached/memory-only (-T). See the
hdparm (8) manpage for the details.
* And of course try the compressed tarball too, since it should be easy
enough and should give you compressable vs. uncompressable numbers for
sanity checking.
--
Duncan - List replies preferred. No HTML msgs.
"Every nonfree program has a lord, a master --
and if you use the program, he is your master." Richard Stallman
prev parent reply other threads:[~2018-04-29 8:30 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-04-27 17:41 NVMe SSD + compression - benchmarking Brendan Hide
2018-04-28 2:05 ` Qu Wenruo
2018-04-28 7:30 ` Brendan Hide
2018-04-29 8:28 ` Duncan [this message]
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