On 10/28/2014 09:59 AM, Markus Trippelsdorf wrote:
On 2014.10.27 at 23:01 +0100, Vlastimil Babka wrote:
On 10/27/2014 09:40 PM, Markus Trippelsdorf wrote:
On my v3.18-rc2 kernel isolate_freepages_block() sometimes shows up very
high (>20%) in perf top during the configuration phase of software
builds. It increases build time considerably.
Unfortunately the issue is not 100% reproducible, because it appears
only intermittently. And the symptoms vanish after a few minutes.
Does it happen for long enough so you can capture it by perf record -g ?
It only happens when I use the "Lockless Allocator":
http://locklessinc.com/downloads/lockless_allocator_src.tgz
I use: LD_PRELOAD=/usr/lib/libllalloc.so.1.3 when building software,
because it gives me a ~8% speed boost over glibc's malloc.
Hm I see. I'll try to test that.
Unfortunately, I don't have time to debug this further and have disabled
"Transparent Hugepage Support" for now.
That's unfortunate indeed. Commit
e14c720efdd73c6d69cd8d07fa894bcd11fe1973 "mm, compaction: remember
position within pageblock in free pages scanner" would be the most
suspicious one here I guess, so testing at least a kernel with this
patch reverted would be very useful. Simple git revert seems to apply
cleanly here.
Thanks,
Vlastimil
--
To unsubscribe, send a message with 'unsubscribe linux-mm' in
the body to majordomo@xxxxxxxxx. For more info on Linux MM,
see: http://www.linux-mm.org/ .
Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>