Hi Jim, Thanks for the reply. It looks like they included this 'compat_ioctl' function pointer in the latest kernel trees. My kernel is 2.6.5. Do BKL is just like any spin_lock? Will it block and lock the entire kernel? Even stop I/O to the disk? On 6/14/06, Jim Cromie <jim.cromie@xxxxxxxxx> wrote:
Mohammad Nayyer Zubair wrote: > Hi all, > > I am working on this process which has a lot of pthreads (around 25) > and 4 of them issue a lot of ioctl calls to my kernel module. I notice > that as more pthreads start issuing ioctls, system performance > decreases. > > These threads are writing data to Fibre-Channel attached scsi storage. > > Is it possible the ioctls are slowing down the entire system, not just > the usermode process? > yes - possibly, esp considering existence of these: [PATCH] macros to detect existance of unlocked_ioctl and ioctl_compat *From: *Michael S. Tsirkin *Date: * Thu Jan 06 2005 - 09:06:51 EST from the unlocked_* version, Id guess that lock you observed below is the BKL, and it certainly could be a choke point, esp as youre getting many calls to the ioctl. > I see sys_ioctl() does a lock_kernel()
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