"Chen, Kenneth W" <[EMAIL PROTECTED]> wrote: > > Andrew Morton wrote on Wednesday, March 09, 2005 2:45 PM > > > > > > > Did you generate a kernel profile? > > > > > > Top 40 kernel hot functions, percentage is normalized to kernel > utilization. > > > > > > _spin_unlock_irqrestore 23.54% > > > _spin_unlock_irq 19.27% > > > > Cripes. > > > > Is that with CONFIG_PREEMPT? If so, and if you disable CONFIG_PREEMPT, > > this cost should be accounting the the spin_unlock() caller and we can see > > who the culprit is. Perhaps dio->bio_lock. > > CONFIG_PREEMPT is off. > > Sorry for all the confusion, I probably shouldn't post the first profile > to confuse people. See 2nd profile that I posted earlier (copied here > again). > > scsi_request_fn 7.54% > finish_task_switch 6.25% > __blockdev_direct_IO 4.97% > __make_request 3.87% > scsi_end_request 3.54% > dio_bio_end_io 2.70% > follow_hugetlb_page 2.39% > __wake_up 2.37% > aio_complete 1.82%
What are these percentages? Total CPU time? The direct-io stuff doesn't look too bad. It's surprising that tweaking the direct-io submission code makes much difference. hm. __blockdev_direct_IO() doesn't actually do much. I assume your damn compiler went and inlined direct_io_worker() on us. - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
