From: rcpilot2010@gmail.com (Abu Rasheda)
To: kernelnewbies@lists.kernelnewbies.org
Subject: Module vs Kernel main performacne
Date: Wed, 30 May 2012 14:44:04 -0700 [thread overview]
Message-ID: <CACYKDtg6b4Ec4NLPJsWxK7zzhMyk-h-tgwoetLQX+p7Ck4gSnw@mail.gmail.com> (raw)
In-Reply-To: <CAGdaadazeyRAgfSxFTXCbTB5Jv_1RTtz=7gzADvxKUih3ueiMQ@mail.gmail.com>
I did another experiment.
Wrote a stand alone module and user program which does ioctl and pass
buffer to kernel module.
User program passes a buffer through ioctl and kernel module does
kmalloc on it and calls copy_from_user, kfree and return. Test program
send 120 gigabyte data to module.
If I pass 1k buffer per call, I get
115,396,349,819 instructions # 0.90 insns per cycle
[95.00%]
as I increase size of buffer, insns per cycle keep decreasing. Here is the data:
1k 0.90 insns per cycle
8k 0.43 insns per cycle
43k 0.18 insns per cycle
100k 0.08 insns per cycle
Showing that cop_from_user is more efficient when copy data is small,
why it is so ?
next prev parent reply other threads:[~2012-05-30 21:44 UTC|newest]
Thread overview: 16+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-05-29 23:50 Module vs Kernel main performacne Abu Rasheda
2012-05-30 4:18 ` Mulyadi Santosa
2012-05-30 4:51 ` Abu Rasheda
2012-05-30 16:45 ` Mulyadi Santosa
2012-05-30 21:44 ` Abu Rasheda [this message]
2012-05-31 0:17 ` Abu Rasheda
2012-05-31 5:35 ` Mulyadi Santosa
2012-05-31 13:35 ` Abu Rasheda
2012-06-01 0:27 ` Chetan Nanda
2012-06-01 18:52 ` Abu Rasheda
2012-06-07 13:11 ` Peter Senna Tschudin
2012-06-07 17:47 ` Abu Rasheda
2012-06-07 18:10 ` Peter Senna Tschudin
2012-06-09 1:52 ` Abu Rasheda
2012-06-07 23:36 ` Peter Senna Tschudin
2012-06-07 23:41 ` Abu Rasheda
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