Re: CONFIG_NO_HZ breaks blktrace timestamps

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

On Fri, Jan 11 2008, Ingo Molnar wrote:
> * Jens Axboe <jens.axboe@xxxxxxxxxx> wrote:
> > > they are from the scheduler git tree (except the first debug patch), 
> > > but queued up for v2.6.25 at the moment.
> > 
> > So this means that blktrace will be broken with CONFIG_NO_HZ for 
> > 2.6.24? That's clearly a regression.
> 64-bit CONFIG_NO_HZ is a new feature in v2.6.24. If it happens on 32-bit 
> too and it didnt happen in v2.6.23 32-bit then it's a regression.

If blktrace worked in 2.6.23 and it doesn't in 2.6.24 because of some
option that isn't immediately apparent, then it's a regression. Period.

> all this comes from blktrace's original decision of using sched_clock()
> :-) It's not a global timesource and it's not trivial to turn it into a
> halfways usable global timesource.

Hey, it was a high res time source and the only one easily available :)
I'm fine with using another timesource, I'll take suggestions or patches
any day!

Jens Axboe

To unsubscribe from this list: send the line "unsubscribe linux-btrace" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at

[Netdev]     [Linux Wireless]     [Kernel Newbies]     [Memory]     [Security]     [Linux for Hams]     [Netfilter]     [Bugtraq]     [Photo]     [Yosemite]     [Yosemite News]     [MIPS Linux]     [ARM Linux]     [Linux RAID]     [Linux Admin]     [Samba]     [Video 4 Linux]     [Linux Resources]

Add to Google