Messages in this thread | | | Date | Wed, 27 Feb 2002 02:55:51 +0100 | From | Matthias Andree <> | Subject | Revisiting 2.4.X __alloc_pages: X-order allocation failed |
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Hi,
I recently had troubles with excessively low I/O throughput when writing a CD from an ISO image. The image file was on a reiserfs partition on an IBM DCAS-32160 (USCSI), attached to an AHA2940Udontaskme (AIC7881U), the writer is ATAPI 16x. Pentium-II/400, 256 MB, PIIX4 IDE chip (BX chip set I believe). SuSE official 2.4.16 kernel as offered as update for SuSE 7.3 -- I didn't check their patches, but their recent kernels were based on -aa stuff AFAICS.
The low throughput showed in a big (16M) but empty (0 - 4%) cdrecord FIFO, with the drive pausing during the write (didn't harm, burnproof was on). 2400 kByte/s (for 16x CD writing) is far below the sustained transfer rates which range from 4.7 at ID to 7.7 MB/s at OD.
This problem didn't show with vanilla 2.4.14.
I found a lot of __alloc_pages: X-order allocation failed in my logs, with X from 1 to 3. Do these allocation failures impair I/O throughput when reading stuff from a disk, tossing things through a statically-allocated FIFO to a CD writer? If so, I might need to give that box some other kernel.
-- Matthias Andree
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