Hello, > Gesendet: Mittwoch, 19. Juni 2013 um 21:39 Uhr > Von: "Nicolás Alvarez" <[email protected]>
> 2013/6/18 Heinz-Bernd Eggenstein <[email protected]>: > > Hi all, > > > > Interesting. I guess it would be useful to run BOINC on a dedicated > > partition (e.g. ext hard disk/ USB stick) to isolate BOINC's contribution > > to the stats. > > Or drop iostat and use iotop instead, which gives realtime I/O stats > per *thread*. Many thanks for the suggestion. Done it. It is not the boinc client but the scientific applications that make up for the IO. But that was not so much disputed. The remaining question is about how much of that IO is due to the * file based shared memory * status updates * checkpointing * the respective app's intrinsic purpose To help the interpretation of iotop, please feel reminded that the average persecond rate in KB/s for an average 2GB/s is > (2*1024*1024*1024)/(60*60*1024) [1] 582.5422 Averaged over 10 seconds, I get typically values between 50 and 150KB/s Total DISK READ : 0.00 B/s | Total DISK WRITE : 55.31 K/s Actual DISK READ: 0.00 B/s | Actual DISK WRITE: 68.83 K/s TID PRIO USER DISK READ DISK WRITE SWAPIN IO> COMMAND 2337 be/4 root 0.00 B/s 0.00 B/s 0.00 % 0.06 % [flush-8:0] 4095 idle boinc 0.00 B/s 7.56 K/s 0.00 % 0.05 % ../../projects/boinc.bakerlab.org_rosetta/minirosetta_3~watchdog -run::rng mt19937 -constant_seed -jran 3111937 4068 idle boinc 0.00 B/s 4.77 K/s 0.00 % 0.03 % ../../projects/boinc.bakerlab.org_rosetta/minirosetta_3~watchdog -run::rng mt19937 -constant_seed -jran 3160216 4675 idle boinc 0.00 B/s 9.15 K/s 0.00 % 0.02 % ../../projects/boinc.bakerlab.org_rosetta/minirosetta_3~watchdog -run::rng mt19937 -constant_seed -jran 3030191 3589 idle boinc 0.00 B/s 9.95 K/s 0.00 % 0.01 % ../../projects/boinc.bakerlab.org_rosetta/minirosetta_3~watchdog -run::rng mt19937 -constant_seed -jran 3194037 4401 idle boinc 0.00 B/s 4.38 K/s 0.00 % 0.01 % ../../projects/boinc.bakerlab.org_rosetta/minirosetta_3~watchdog -run::rng mt19937 -constant_seed -jran 3075156 4132 idle boinc 0.00 B/s 6.76 K/s 0.00 % 0.00 % ../../projects/boinc.bakerlab.org_rosetta/minirosetta_3~watchdog -run::rng mt19937 -constant_seed -jran 3764396 4133 idle boinc 0.00 B/s 407.43 B/s 0.00 % 0.00 % ../../projects/boinc.bakerlab.org_rosetta/minirosetta_3~watchdog -run::rng mt19937 -constant_seed -jran 3764396 18744 idle boinc 0.00 B/s 1222.28 B/s 0.00 % 0.00 % boinc --check_all_logins --redirectio --dir /var/lib/boinc-client 1022 idle boinc 0.00 B/s 6.37 K/s 0.00 % 0.00 % ../../projects/boinc.bakerlab.org_rosetta/minirosetta_3~watchdog -run::rng mt19937 -constant_seed -jran 3231298 3869 idle boinc 0.00 B/s 4.77 K/s 0.00 % 0.00 % ../../projects/boinc.bakerlab.org_rosetta/minirosetta_3~watchdog -run::rng mt19937 -constant_seed -jran 3180570 4096 idle boinc 0.00 B/s 0.00 B/s 0.00 % 0.00 % ../../projects/boinc.bakerlab.org_rosetta/minirosetta_3~watchdog -run::rng mt19937 -constant_seed -jran 3111937 and while run over 10 minutes, iostat gives $ date; iostat -h -m; sleep 600; date; iostat -h -m Thu Jun 20 12:04:04 CEST 2013 Device: tps MB_read/s MB_wrtn/s MB_read MB_wrtn sda 3.27 0.02 0.35 29254 668009 Thu Jun 20 12:14:04 CEST 2013 Device: tps MB_read/s MB_wrtn/s MB_read MB_wrtn sda 3.27 0.02 0.36 29254 668359 So, over 10 minutes, we still have a 35 MB/(60s) = 597KB/s and the ever reported 2 GB/h. One of my first actions after reading the initial iostat output (not shown) was to have the ext4 formatted root partition to receive the extra option "commit=60". The noatime was already set. All data presented here were taken after that change. The file mapping of shared memory seems to be generally accepted as a possible IO trap, as seen e.g. here http://serverfault.com/questions/361032/high-disk-i-o-when-cache-is-used . It seems a bit like the scientific applications have some bits here and there to tune their IO behaviour. Running Milkyway 0.18 for instance, I see no IO for the clients at all while they went from 5% to 27%. I have locally implemented a patch for (presumed) diskless shared memory. You can have a look over here http://anonscm.debian.org/gitweb/?p=pkg-boinc/boinc.git;a=blob;f=debian/patches/mmap_mem_only.patch;hb=HEAD Again: it is not applied in Debian's regular BOINC packages but needs to be commented in in debian/patches/series. I'll report if it works and about respective effects on SETI (may required a recompilation) next week. Best, Steffen _______________________________________________ boinc_dev mailing list [email protected] http://lists.ssl.berkeley.edu/mailman/listinfo/boinc_dev To unsubscribe, visit the above URL and (near bottom of page) enter your email address.
