Re: jemalloc and transparent hugepage

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>>Is this something we can set with mallctl[1] at startup? 

I don't think it's possible.

TP hugepage are managed by kernel, not jemalloc.

(but a simple "echo never > /sys/kernel/mm/transparent_hugepage/enabled" in init script is enough)

----- Mail original -----
De: "Sage Weil" <sweil@xxxxxxxxxx>
À: "aderumier" <aderumier@xxxxxxxxx>
Cc: "Mark Nelson" <mnelson@xxxxxxxxxx>, "ceph-devel" <ceph-devel@xxxxxxxxxxxxxxx>, "ceph-users" <ceph-users@xxxxxxxxxxxxxx>, "Somnath Roy" <somnath.roy@xxxxxxxxxxx>
Envoyé: Mercredi 9 Septembre 2015 04:07:59
Objet: Re:  jemalloc and transparent hugepage

On Wed, 9 Sep 2015, Alexandre DERUMIER wrote: 
> >>Have you noticed any performance difference with tp=never? 
> 
> No difference. 
> 
> I think hugepage could speedup big memory sets like 100-200GB, but for 
> 1-2GB they are no noticable difference. 

Is this something we can set with mallctl[1] at startup? 

sage 

[1] http://www.canonware.com/download/jemalloc/jemalloc-latest/doc/jemalloc.html 

> 
> 
> 
> 
> 
> 
> ----- Mail original ----- 
> De: "Mark Nelson" <mnelson@xxxxxxxxxx> 
> À: "aderumier" <aderumier@xxxxxxxxx>, "ceph-devel" <ceph-devel@xxxxxxxxxxxxxxx>, "ceph-users" <ceph-users@xxxxxxxxxxxxxx> 
> Cc: "Somnath Roy" <somnath.roy@xxxxxxxxxxx> 
> Envoyé: Mercredi 9 Septembre 2015 01:49:35 
> Objet: Re:  jemalloc and transparent hugepage 
> 
> Excellent investigation Alexandre! Have you noticed any performance 
> difference with tp=never? 
> 
> Mark 
> 
> On 09/08/2015 06:33 PM, Alexandre DERUMIER wrote: 
> > I have done small benchmark with tcmalloc and jemalloc, transparent hugepage=always|never. 
> > 
> > for tcmalloc, they are no difference. 
> > but for jemalloc, the difference is huge (around 25% lower with tp=never). 
> > 
> > jemmaloc 4.6.0+tp=never vs tcmalloc use 10% more RSS memory 
> > 
> > jemmaloc 4.0+tp=never almost use same RSS memory than tcmalloc ! 
> > 
> > 
> > I don't have monitored memory usage in recovery, but I think it should help too. 
> > 
> > 
> > 
> > 
> > tcmalloc 2.1 tp=always 
> > ------------------- 
> > USER PID %CPU %MEM VSZ RSS TTY STAT START TIME COMMAND 
> > 
> > root 67746 120 1.0 1531220 671152 ? Ssl 01:18 0:43 /usr/bin/ceph-osd --cluster=ceph -i 0 -f 
> > root 67764 144 1.0 1570256 711232 ? Ssl 01:18 0:51 /usr/bin/ceph-osd --cluster=ceph -i 1 -f 
> > 
> > root 68363 220 0.9 1522292 655888 ? Ssl 01:19 0:46 /usr/bin/ceph-osd --cluster=ceph -i 0 -f 
> > root 68381 261 1.0 1563396 702500 ? Ssl 01:19 0:55 /usr/bin/ceph-osd --cluster=ceph -i 1 -f 
> > 
> > root 68963 228 1.0 1519240 666196 ? Ssl 01:20 0:31 /usr/bin/ceph-osd --cluster=ceph -i 0 -f 
> > root 68981 268 1.0 1564452 694352 ? Ssl 01:20 0:37 /usr/bin/ceph-osd --cluster=ceph -i 1 -f 
> > 
> > 
> > 
> > tcmalloc 2.1 tp=never 
> > ----------------- 
> > USER PID %CPU %MEM VSZ RSS TTY STAT START TIME COMMAND 
> > 
> > root 69560 144 1.0 1544968 677584 ? Ssl 01:21 0:20 /usr/bin/ceph-osd --cluster=ceph -i 0 -f 
> > root 69578 167 1.0 1568620 704456 ? Ssl 01:21 0:23 /usr/bin/ceph-osd --cluster=ceph -i 1 -f 
> > 
> > 
> > root 70156 164 0.9 1519680 649776 ? Ssl 01:21 0:16 /usr/bin/ceph-osd --cluster=ceph -i 0 -f 
> > root 70174 214 1.0 1559772 692828 ? Ssl 01:21 0:19 /usr/bin/ceph-osd --cluster=ceph -i 1 -f 
> > 
> > root 70757 202 0.9 1520376 650572 ? Ssl 01:22 0:20 /usr/bin/ceph-osd --cluster=ceph -i 0 -f 
> > root 70775 236 1.0 1560644 694088 ? Ssl 01:22 0:23 /usr/bin/ceph-osd --cluster=ceph -i 1 -f 
> > 
> > 
> > 
> > jemalloc 3.6 tp = always 
> > ------------------------ 
> > USER PID %CPU %MEM VSZ RSS TTY STAT START TIME COMMAND 
> > 
> > root 92005 46.1 1.4 2033864 967512 ? Ssl 01:00 0:04 /usr/bin/ceph-osd --cluster=ceph -i 5 -f 
> > root 92027 45.5 1.4 2021624 963536 ? Ssl 01:00 0:04 /usr/bin/ceph-osd --cluster=ceph -i 4 -f 
> > 
> > 
> > 
> > root 92703 191 1.5 2138724 1002376 ? Ssl 01:02 1:16 /usr/bin/ceph-osd --cluster=ceph -i 5 -f 
> > root 92721 183 1.5 2126228 986448 ? Ssl 01:02 1:13 /usr/bin/ceph-osd --cluster=ceph -i 4 -f 
> > 
> > 
> > root 93366 258 1.4 2139052 984132 ? Ssl 01:03 1:09 /usr/bin/ceph-osd --cluster=ceph -i 5 -f 
> > root 93384 250 1.5 2126244 990348 ? Ssl 01:03 1:07 /usr/bin/ceph-osd --cluster=ceph -i 4 -f 
> > 
> > 
> > 
> > jemalloc 3.6 tp = never 
> > ----------------------- 
> > USER PID %CPU %MEM VSZ RSS TTY STAT START TIME COMMAND 
> > 
> > root 93990 238 1.1 2105812 762628 ? Ssl 01:04 1:16 /usr/bin/ceph-osd --cluster=ceph -i 4 -f 
> > root 94033 263 1.1 2118288 781768 ? Ssl 01:04 1:18 /usr/bin/ceph-osd --cluster=ceph -i 5 -f 
> > 
> > 
> > root 94656 266 1.1 2139096 781392 ? Ssl 01:05 0:58 /usr/bin/ceph-osd --cluster=ceph -i 5 -f 
> > root 94674 257 1.1 2126316 760632 ? Ssl 01:05 0:56 /usr/bin/ceph-osd --cluster=ceph -i 4 -f 
> > 
> > root 95317 297 1.1 2135044 780532 ? Ssl 01:06 0:35 /usr/bin/ceph-osd --cluster=ceph -i 5 -f 
> > root 95335 284 1.1 2112016 760972 ? Ssl 01:06 0:34 /usr/bin/ceph-osd --cluster=ceph -i 4 -f 
> > 
> > 
> > 
> > jemalloc 4.0 tp = always 
> > ------------------------ 
> > USER PID %CPU %MEM VSZ RSS TTY STAT START TIME COMMAND 
> > 
> > root 100275 198 1.3 1784520 880288 ? Ssl 01:14 0:45 /usr/bin/ceph-osd --cluster=ceph -i 4 -f 
> > root 100320 239 1.1 1793184 760824 ? Ssl 01:14 0:47 /usr/bin/ceph-osd --cluster=ceph -i 5 -f 
> > 
> > 
> > root 100897 200 1.3 1765780 891256 ? Ssl 01:15 0:50 /usr/bin/ceph-osd --cluster=ceph -i 4 -f 
> > root 100942 245 1.1 1817436 746956 ? Ssl 01:15 0:53 /usr/bin/ceph-osd --cluster=ceph -i 5 -f 
> > 
> > root 101517 196 1.3 1769904 877132 ? Ssl 01:16 0:33 /usr/bin/ceph-osd --cluster=ceph -i 4 -f 
> > root 101562 258 1.1 1805172 746532 ? Ssl 01:16 0:36 /usr/bin/ceph-osd --cluster=ceph -i 5 -f 
> > 
> > 
> > jemalloc 4.0 tp = never 
> > ----------------------- 
> > USER PID %CPU %MEM VSZ RSS TTY STAT START TIME COMMAND 
> > 
> > root 98362 87.8 1.0 1841748 678848 ? Ssl 01:10 0:53 /usr/bin/ceph-osd --cluster=ceph -i 4 -f 
> > root 98405 97.0 1.0 1846328 699620 ? Ssl 01:10 0:56 /usr/bin/ceph-osd --cluster=ceph -i 5 -f 
> > 
> > 
> > 
> > root 99018 233 1.0 1812580 698848 ? Ssl 01:12 0:30 /usr/bin/ceph-osd --cluster=ceph -i 5 -f 
> > root 99036 226 1.0 1822344 677420 ? Ssl 01:12 0:29 /usr/bin/ceph-osd --cluster=ceph -i 4 -f 
> > 
> > root 99666 281 1.0 1814640 696420 ? Ssl 01:13 0:33 /usr/bin/ceph-osd --cluster=ceph -i 5 -f 
> > root 99684 266 1.0 1835676 676768 ? Ssl 01:13 0:32 /usr/bin/ceph-osd --cluster=ceph -i 4 -f 
> > 
> > 
> > 
> > 
> > ----- Mail original ----- 
> > De: "aderumier" <aderumier@xxxxxxxxx> 
> > À: "ceph-devel" <ceph-devel@xxxxxxxxxxxxxxx>, "ceph-users" <ceph-users@xxxxxxxxxxxxxx> 
> > Envoyé: Mardi 8 Septembre 2015 21:42:35 
> > Objet:  jemalloc and transparent hugepage 
> > 
> > Hi, 
> > I have found an interesting article about jemalloc and transparent hugepages 
> > 
> > https://www.digitalocean.com/company/blog/transparent-huge-pages-and-alternative-memory-allocators/ 
> > 
> > 
> > Could be great to see if disable transparent hugepage help to have lower jemalloc memory usage. 
> > 
> > 
> > Regards, 
> > 
> > Alexandre 
> > 
> > _______________________________________________ 
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> > ceph-users@xxxxxxxxxxxxxx 
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