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[Steven Sheehy <steven.sheehy@xxxxxxxxx>]

Fast hashing uses mmap so its memory characteristics are different than
regular hashing. As far as it being slower, what is the result after you
added -m64?

-- 
(Open)Solaris hashing memory issue
https://bugs.launchpad.net/bugs/600815
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Status in Linux DC++: New

Bug description:
LinuxDC++ rev 374. OpenSolaris b134.

When using "fast hashing", I see loads of memory getting lost. It is freed eventually, but it forces by ZFS cache size down which is bad. If I limit the hashing speed to something ... significantly lower than the full speed (81MB/s with "fast hashing"), the pages are freed as they should be, and memory usage is much better.

If I turn off fast hashing, I get around 90MB/s (ie 10% faster), and no more spurious RAM usage. As below.

#fast hashing, unconstrained
$ echo '::memstat' | pfexec mdb -k                        
Page Summary                Pages                MB  %Tot
------------     ----------------  ----------------  ----
Kernel                     624357              2438   30%
ZFS File Data              452437              1767   22%
Anon                       359060              1402   17%
Exec and libs                5295                20    0%
Page cache                 578750              2260   28%     <<<<-----------
Free (cachelist)            66261               258    3%
Free (freelist)              6664                26    0%
 
Total                     2092824              8175
Physical                  2092823              8175
 
#fast hashing, limited to 5MB/s
$ echo '::memstat' | pfexec mdb -k
Page Summary                Pages                MB  %Tot
------------     ----------------  ----------------  ----
Kernel                     632897              2472   30%
ZFS File Data              756611              2955   36%
Anon                       359078              1402   17%
Exec and libs                5288                20    0%
Page cache                  24568                95    1%     <<<<-----------
Free (cachelist)           308583              1205   15%
Free (freelist)              5799                22    0%
 
Total                     2092824              8175
Physical                  2092823              8175

#slow hashing, unlimited
$ echo '::memstat' | pfexec mdb -k
Page Summary                Pages                MB  %Tot
------------     ----------------  ----------------  ----
Kernel                     606479              2369   29%
ZFS File Data             1015465              3966   49%
Anon                       363770              1420   17%
Exec and libs                5248                20    0%
Page cache                  16605                64    1%     <<<<-----------
Free (cachelist)            48231               188    2%
Free (freelist)             37026               144    2%

Total                     2092824              8175
Physical                  2092823              8175