Comments on: How to find per-process I/O statistics on Linux http://www.xaprb.com/blog/2009/08/23/how-to-find-per-process-io-statistics-on-linux/ Stay curious! Thu, 09 Feb 2012 20:41:20 +0000 hourly 1 http://wordpress.org/?v=3.2.1 By: Yong Huang http://www.xaprb.com/blog/2009/08/23/how-to-find-per-process-io-statistics-on-linux/#comment-19029 Yong Huang Mon, 03 Jan 2011 19:48:57 +0000 http://www.xaprb.com/blog/?p=1238#comment-19029 For those trying to get Guillaume Chazarain's sophisticated iotop to work, try my humble little topio program as a workaround: http://yong321.freeshell.org/freeware/pio.html#linux Over the past 7 years, I ported my program to multiple OS'es. The Linux version was done only a few months ago. For those trying to get Guillaume Chazarain’s sophisticated iotop to work, try my humble little topio program as a workaround:
http://yong321.freeshell.org/freeware/pio.html#linux

Over the past 7 years, I ported my program to multiple OS’es. The Linux version was done only a few months ago.

]]> By: Greg Smith http://www.xaprb.com/blog/2009/08/23/how-to-find-per-process-io-statistics-on-linux/#comment-19026 Greg Smith Mon, 03 Jan 2011 19:02:48 +0000 http://www.xaprb.com/blog/?p=1238#comment-19026 The unit for block_dump data is blocks, and the easiest way to determine that size in a way that works for any filesystem type is: /sbin/blockdev --getbsz /dev/sda1 Note that even though I/O accounting showed up in RHEL 5.4, you still can't get iotop to work because of other dependencies. As of iotop 0.4, it will compile and run against the Python 2.4 included with RHEL, so long as you've installed the python-ctypes package. But iotop still doesn't work. Even though the main per-process I/O patch was backported in RHEL 5.4, the current kernel isn't configured correctly for it, and there are other issues with the backport being incomplete. If you build iotop and run it, against the most recent RHEL 5.5 kernel I have here (2.6.18-194.26) it gives the error "CONFIG_TASK_DELAY_ACCT not enabled in kernel, cannot determine SWAPIN and IO %" and the detail level is accordingly low. There is an open enhancement request to sort this out so iotop works: https://bugzilla.redhat.com/show_bug.cgi?id=557062 but it keeps missing being included in RHEL releases. It was hoped for in 5.6 but missed that deadline. The kernel patches needed are available (along with RHEL engineer packaged iotop related RPMs) are available at http://people.redhat.com/jolsa/iotop/ ; while the patches there aren't large, it isn't as easy as just turning on the kernel config option. The unit for block_dump data is blocks, and the easiest way to determine that size in a way that works for any filesystem type is:

/sbin/blockdev –getbsz /dev/sda1

Note that even though I/O accounting showed up in RHEL 5.4, you still can’t get iotop to work because of other dependencies. As of iotop 0.4, it will compile and run against the Python 2.4 included with RHEL, so long as you’ve installed the python-ctypes package. But iotop still doesn’t work. Even though the main per-process I/O patch was backported in RHEL 5.4, the current kernel isn’t configured correctly for it, and there are other issues with the backport being incomplete. If you build iotop and run it, against the most recent RHEL 5.5 kernel I have here (2.6.18-194.26) it gives the error “CONFIG_TASK_DELAY_ACCT not enabled in kernel, cannot determine SWAPIN and IO %” and the detail level is accordingly low.

There is an open enhancement request to sort this out so iotop works: https://bugzilla.redhat.com/show_bug.cgi?id=557062 but it keeps missing being included in RHEL releases. It was hoped for in 5.6 but missed that deadline. The kernel patches needed are available (along with RHEL engineer packaged iotop related RPMs) are available at http://people.redhat.com/jolsa/iotop/ ; while the patches there aren’t large, it isn’t as easy as just turning on the kernel config option.

]]> By: terrabit http://www.xaprb.com/blog/2009/08/23/how-to-find-per-process-io-statistics-on-linux/#comment-18987 terrabit Sat, 18 Dec 2010 07:41:50 +0000 http://www.xaprb.com/blog/?p=1238#comment-18987 Here is the script : #!/bin/bash dmesg -c echo 1 > /proc/sys/vm/block_dump sleep 30 go=0 while [ $go = 0 ]; do sleep 1 clear dmesg | perl iodump trap "go=1" SIGINT done echo 0 > /proc/sys/vm/block_dump dmesg -c clear echo Caught SIGINT. Here is the script :

#!/bin/bash
dmesg -c
echo 1 > /proc/sys/vm/block_dump
sleep 30
go=0
while [ $go = 0 ]; do
sleep 1
clear
dmesg | perl iodump
trap “go=1″ SIGINT
done
echo 0 > /proc/sys/vm/block_dump
dmesg -c
clear
echo Caught SIGINT.

]]> By: Yong Huang http://www.xaprb.com/blog/2009/08/23/how-to-find-per-process-io-statistics-on-linux/#comment-18922 Yong Huang Wed, 17 Nov 2010 15:59:11 +0000 http://www.xaprb.com/blog/?p=1238#comment-18922 Looks like the unit is simply "times", like when you ask How many times has this process done READ's (or WRITE's)? Every time, a READ (or WRITE) reads (writes) one block. Not sure how vm/block_dump records scatter/gather I/O (multiple blocks per read or write). I guess it breaks it up into multiple READ/WRITE lines but I'm not sure. The next question is How big is the block? I'm pretty sure it's the file system block size as when you created the file system. With that info, you can convert the iodump result into KB or MB. Looks like the unit is simply “times”, like when you ask How many times has this process done READ’s (or WRITE’s)? Every time, a READ (or WRITE) reads (writes) one block. Not sure how vm/block_dump records scatter/gather I/O (multiple blocks per read or write). I guess it breaks it up into multiple READ/WRITE lines but I’m not sure. The next question is How big is the block? I’m pretty sure it’s the file system block size as when you created the file system. With that info, you can convert the iodump result into KB or MB.

]]> By: Xaprb http://www.xaprb.com/blog/2009/08/23/how-to-find-per-process-io-statistics-on-linux/#comment-18800 Xaprb Tue, 19 Oct 2010 10:47:35 +0000 http://www.xaprb.com/blog/?p=1238#comment-18800 I don't remember. If you find out, post the answer in a new comment. I don’t remember. If you find out, post the answer in a new comment.

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