I gave the O_STREAMING in Andrew's 2.5-mm tree the treatment..
Short summary: It works.
The streaming read test in the following benchmarks is simply a read()
in 64KB byte chunks of an 800MB file.
First test. Show the cache effects are indeed as we intend and the
overhead is negligible. Here, mem=2G.
O_STREAMING? Wall time Cache Delta
Yes 21.827s 0
No 21.734s +800MB
Second test. Same deal, but mem=8M. There was slight swapping, so I
suspect the reduced VM pressure is why the O_STREAMING run is faster.
O_STREAMING? Wall time Cache Delta
Yes 22.303s 0
No 28.812s +1MB
Third and final test. Kernel compile (make -j2) with a couple streaming
reads in the background. Again, mem=2G. This shows that actually
saving the pagecache from the horrid waste is useful.
O_STREAMING Wall time to complete Kernel compile
Yes 5m30.494s
No 4m59.661s
So, uh, Andrew's 2.5 code works ;-)
Someone buy me a dual Xeon,
Robert Love
-
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/
This archive was generated by hypermail 2b29 : Wed Oct 23 2002 - 22:00:31 EST