Subject: [linux-audio-dev] File writes with O_SYNC slow
From: Karl JH Millar (kmillar_AT_MIT.EDU)
Date: Wed Apr 19 2000 - 18:55:04 EEST
Hi,
I've noticed that file writes with O_SYNC are very much slower than they should
be. On my disk (IDE, DMA not working) hdparm shows me 4MB/sec data transfers.
Writing data using O_SYNC, I get less than 0.1MB/sec. If instead of opening
the file with O_SYNC I open it normally and follow each write with a call
to fsync, I get 1MB/sec, while doing the same amount of I/O.
This is all using kernel 2.2.14, and an ext2 filesystem.
What's going on here?
Karl.
(BTW Benno, putting a fsync(fd) after the writes in buffer.cpp on your hdrbench
gives me significant improvement)
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