Ritesh Raj Sarraf wrote: > I'm using dm-crypt on an external USB enclosure ide hdd. I copied 20Gb of > data on to the encrypted device and am suffering severe performance penalty. > After a couple of seconds, all processes involved in the I/O keep stalling. > They periodically resume, just for a couple of seconds and then again stall. > > Running linux 2.6.26. Please can you try it without dm-crypt involved? Just copy 20Gb to your unencrypted disk attached through USB. I saw this problem with plain USB attached storage some time ago too. There is only one thread in dm-crypt and it is waiting for io_schedule, so I think it is not dm-crypt who is blocking it, but the layer below the dm-crypt. Milan > [15869.848387] kcryptd D f7044a0c 0 13656 2 > [15869.848387] f29d79c0 00000046 01c58000 f7044a0c c03c1430 c03c4740 > c03c4740 f29d79c0 > [15869.848387] f29d7b4c c201c740 00000001 00010001 00000001 f79b48d0 > f29d7b4c 00eb4b70 > [15869.848387] c01df9a6 c0135b72 00000000 00000000 00000000 000000ff > c201c740 c201cb44 > [15869.848387] Call Trace: > [15869.848387] [<c01df9a6>] cfq_may_queue+0x48/0xab > [15869.848387] [<c0135b72>] getnstimeofday+0x32/0xaf > [15869.848387] [<c02c1091>] io_schedule+0x4f/0x86 > [15869.848387] [<c01d734f>] get_request_wait+0xf2/0x16d > [15869.848387] [<c013140a>] autoremove_wake_function+0x0/0x2d > [15869.848387] [<c01d7789>] __make_request+0x2b7/0x33a > [15869.848387] [<c01d6465>] generic_make_request+0x419/0x44a > [15869.848387] [<f8c30563>] async_encrypt+0x2f/0x35 [crypto_blkcipher] > [15869.848387] [<f8c659ce>] crypt_convert+0x20e/0x240 [dm_crypt] > [15869.848387] [<f8c65c5d>] kcryptd_crypt+0x25d/0x339 [dm_crypt] > [15869.848387] [<f8c65a00>] kcryptd_crypt+0x0/0x339 [dm_crypt] > [15869.848387] [<f8c65a00>] kcryptd_crypt+0x0/0x339 [dm_crypt] > [15869.848387] [<c012e818>] run_workqueue+0x73/0xed > [15869.848387] [<c012e949>] worker_thread+0xb7/0xc3 > [15869.848387] [<c013140a>] autoremove_wake_function+0x0/0x2d > [15869.848387] [<c012e892>] worker_thread+0x0/0xc3 > [15869.848387] [<c01311a6>] kthread+0x38/0x5d > [15869.848387] [<c013116e>] kthread+0x0/0x5d > [15869.848387] [<c01045af>] kernel_thread_helper+0x7/0x10 Milan -- mbroz@xxxxxxxxxx -- dm-devel mailing list dm-devel@xxxxxxxxxx https://www.redhat.com/mailman/listinfo/dm-devel
