We are working on a project to improve the disk performance. We saw that the IO schedulers are implemented as modules. However, we cannot find them in /proc/modules. Can anyone tell why this is so. We want to change a few things in these modules and test the performance by reinserting them. Are we missing something?? Thanks, Paresh _______________________________________________ Xen-devel mailing list Xen-devel@lists.xensource.com http://lists.xensource.com/xen-devel
On Fri, Feb 04, 2011 at 06:00:34PM +0530, Paresh Nakhe wrote:> We are working on a project to improve the disk performance. We saw that > the IO schedulers are implemented as modules. > However, we cannot find them in /proc/modules. Can anyone tell why this is > so. > > We want to change a few things in these modules and test the performance > by reinserting them. Are we missing something?? >IO schedulers (elevators) are *Linux* kernel feature, so the question is how did you configure the *Linux* kernel you''re using? Are we talking about dom0 or domU here? -- Pasi _______________________________________________ Xen-devel mailing list Xen-devel@lists.xensource.com http://lists.xensource.com/xen-devel
I was talking about dom0 here. We know that IO schedulers can be switched at runtime. They are not fixed at compile time configuration. After going through the code for IO schedulers, we realized that these were actually modules. If this is the case, we should be able to see them in /proc/modules which is not happening. Paresh On Fri, Feb 4, 2011 at 8:41 PM, Pasi Kärkkäinen <pasik@iki.fi> wrote:> On Fri, Feb 04, 2011 at 06:00:34PM +0530, Paresh Nakhe wrote: > > We are working on a project to improve the disk performance. We saw > that > > the IO schedulers are implemented as modules. > > However, we cannot find them in /proc/modules. Can anyone tell why > this is > > so. > > > > We want to change a few things in these modules and test the > performance > > by reinserting them. Are we missing something?? > > > > IO schedulers (elevators) are *Linux* kernel feature, > so the question is how did you configure the *Linux* kernel you''re using? > > Are we talking about dom0 or domU here? > > -- Pasi > >-- *What I have is not a dream, because I will make it a reality.* _______________________________________________ Xen-devel mailing list Xen-devel@lists.xensource.com http://lists.xensource.com/xen-devel
Please don''t top post. On Fri, 2011-02-04 at 15:34 +0000, Paresh Nakhe wrote:> I was talking about dom0 here. We know that IO schedulers can be > switched at runtime. They are not fixed at compile time configuration. > > After going through the code for IO schedulers, we realized that these > were actually modules. If this is the case, we should be able to see > them in /proc/modules which is not happening./proc/modules is core kernel functionality and I don''t see how this behaviour would differ from native. Modules don''t actually show up in /proc/modules until you load them. This works for me. quartz:~# modprobe deadline-iosched quartz:~# cat /proc/modules deadline_iosched 3671 0 - Live 0xf90e0000 nfsd 83866 11 - Live 0xf9098000 exportfs 3143 1 nfsd, Live 0xf8f08000 rtc_cmos 8147 0 - Live 0xf7c62000 rtc_core 14509 1 rtc_cmos, Live 0xf7c35000 rtc_lib 2428 1 rtc_core, Live 0xf7c04000 Ian. _______________________________________________ Xen-devel mailing list Xen-devel@lists.xensource.com http://lists.xensource.com/xen-devel
On Fri, Feb 4, 2011 at 9:21 PM, Ian Campbell <Ian.Campbell@citrix.com>wrote:> Please don''t top post. > > On Fri, 2011-02-04 at 15:34 +0000, Paresh Nakhe wrote: > > I was talking about dom0 here. We know that IO schedulers can be > > switched at runtime. They are not fixed at compile time configuration. > > > > After going through the code for IO schedulers, we realized that these > > were actually modules. If this is the case, we should be able to see > > them in /proc/modules which is not happening. > > /proc/modules is core kernel functionality and I don''t see how this > behaviour would differ from native. > > Modules don''t actually show up in /proc/modules until you load them. > This works for me. > > quartz:~# modprobe deadline-iosched > quartz:~# cat /proc/modules > deadline_iosched 3671 0 - Live 0xf90e0000 > nfsd 83866 11 - Live 0xf9098000 > exportfs 3143 1 nfsd, Live 0xf8f08000 > rtc_cmos 8147 0 - Live 0xf7c62000 > rtc_core 14509 1 rtc_cmos, Live 0xf7c35000 > rtc_lib 2428 1 rtc_core, Live 0xf7c04000 > > Ian. > > >root@paresh-hp:~# modprobe deadline-iosched it is not showing the module after lsmod as in your case. root@paresh-hp:~# rmmod deadline-iosched ERROR: Module deadline_iosched does not exist in /proc/modules (same for cfq-iosched) root@paresh-hp:~# modprobe noop-iosched FATAL: Module noop_iosched not found. What could be the reason for this?? Anyways, if we modify the code, create a makefile, compile and load the module then there should not be any problem right?? Would it give an error saying that we are re-inserting an existing module?? _______________________________________________ Xen-devel mailing list Xen-devel@lists.xensource.com http://lists.xensource.com/xen-devel
On Fri, 2011-02-04 at 16:23 +0000, Paresh Nakhe wrote:> What could be the reason for this??What kernel version are you using? what is your .config? Does this behave as expected on native? Ian. _______________________________________________ Xen-devel mailing list Xen-devel@lists.xensource.com http://lists.xensource.com/xen-devel
On Fri, Feb 4, 2011 at 9:58 PM, Ian Campbell <Ian.Campbell@eu.citrix.com>wrote:> On Fri, 2011-02-04 at 16:23 +0000, Paresh Nakhe wrote: > > What could be the reason for this?? > > What kernel version are you using? what is your .config? Does this > behave as expected on native? > > Ian. > > >I am using 2.6.35 and currently on native machine only. Part of .config # # IO Schedulers # CONFIG_IOSCHED_NOOP=y CONFIG_IOSCHED_DEADLINE=y CONFIG_IOSCHED_CFQ=y # CONFIG_DEFAULT_DEADLINE is not set CONFIG_DEFAULT_CFQ=y # CONFIG_DEFAULT_NOOP is not set CONFIG_DEFAULT_IOSCHED="cfq" CONFIG_PREEMPT_NOTIFIERS=y CONFIG_PADATA=y _______________________________________________ Xen-devel mailing list Xen-devel@lists.xensource.com http://lists.xensource.com/xen-devel
On Fri, 2011-02-04 at 16:44 +0000, Paresh Nakhe wrote:> I am using 2.6.35 and currently on native machine only.So why did you think xen-devel would be an appropriate forum for this issue?> Part of .config > > # > # IO Schedulers > # > CONFIG_IOSCHED_NOOP=y > CONFIG_IOSCHED_DEADLINE=y > CONFIG_IOSCHED_CFQ=yAll of which are quite clearly built statically into the kernel and are not modular. Please, xen-devel is not an appropriate list to seek help with basic Linux kernel development issues and/or trouble shooting when not specifically running under Xen. Ian. _______________________________________________ Xen-devel mailing list Xen-devel@lists.xensource.com http://lists.xensource.com/xen-devel