Messages in this thread | | | Date | Wed, 1 Feb 2006 22:07:52 +0100 | From | JG <> | Subject | 100% cpu usage (kjournald, pdflush) with encrypted disks (dm-crypt) |
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hi,
i've also posted this to dm-crypt mailing list, but here is some additional info.
i've encrypted my hard disks (whole root, and other disks) with "cryptsetup luksFormat --cipher aes-cbc-essiv:sha256 --key-size 256" and formatted them with ext3 (-j -m0 -O dir_index).
i'm using 2.6.15.1 kernel on an athlon xp 2400+ with 1GB RAM, VIA KT400A/VT8237 chipset.
/proc/crypto for aes: name : aes module : kernel type : cipher blocksize : 16 min keysize : 16 max keysize : 32
i searched for the aes-i586 optimization (that should be in the kernel?) but i found no other reference to it than CONFIG_CRYPTO_AES_586=y. guess i'm using the asm optimized code as there is no other AES option in the kernel.
if i copy files from one encrypted disk to another my cpu usage goes up to 100% and stays there for the whole copy process. renicing cp itself doesn't help.
hdparm settings are the same for all disks except the SATA ones. multcount = 16 (on) IO_support = 3 (32-bit w/sync) unmaskirq = 1 (on) using_dma = 1 (on) keepsettings = 0 (off) readonly = 0 (off) readahead = 256 (on)
kjournald and pdflush use all the cpu time, where kjournald is usually at about 40-70% and pdflush goes up to 50-60%. this is while copying large files. the cpu usage of kcryptd is negligible.
if i copy many small files, kcryptd will eat much more cpu, about 30-40% and the rest will be pdflush and kjournald.
all disks are mounted with -o defaults,noatime.
doing a 'mke2fs -j -m0 -O dir_index /dev/mapper/name' will also rise the cpu usage to its maximum where pdflush takes about 60-70%. (mke2fs 1.38 (30-Jun-2005) Using EXT2FS Library version 1.38)
is anyone else seeing this and is there a solution (besides using a non-journalling fs) or do i have to live with it that encryption eats all my cpu?
tx, JG - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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