Re: Lockless page cache test results

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

 



Andrew Morton wrote:

The top of the 4-client
vanilla run profile looks like this:

samples  %        symbol name
65328    47.8972  find_get_page

Basically the machine is fully pegged, about 7% idle time.


Most of the time an acquisition of tree_lock is associated with a disk
read, or a page-size memset, or a page-size memcpy.  And often an
acquisition of tree_lock is associated with multiple pages, not just a
single page.

Still, most of the times it is acquired would be once per page for
read, write, nopage.

For read and write, often it will be a full page memcpy but even such
a memcpy operation can quickly become insignificant compared to tl
contention.

Anyway, whatever. What needs to be demonstrated are real world
improvements at the end of the day.


So although the graph looks good, I wouldn't view this as a super-strong
argument in favour of lockless pagecache.

No. Cool numbers though ;)

--
SUSE Labs, Novell Inc.

Send instant messages to your online friends http://au.messenger.yahoo.com -
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/

[Index of Archives]     [Kernel Newbies]     [Netfilter]     [Bugtraq]     [Photo]     [Stuff]     [Gimp]     [Yosemite News]     [MIPS Linux]     [ARM Linux]     [Linux Security]     [Linux RAID]     [Video 4 Linux]     [Linux for the blind]     [Linux Resources]
  Powered by Linux