On Thursday, 22 March 2012 at 04:29:41 UTC, Jay Norwood wrote:
On the use of larger files ... yes that will be interesting,
but for these current measurements the file reads are only
taking on the order of 30ms for 20MB, which tells me they are
already either being cached by win7, or else by the ssd's cache.
I'll use the article instructions below and put the files
being read into the cache prior to the test, so that the file
read time should be small and consistent relative to the other
buffer processing time inside the loops.
http://us.generation-nt.com/activate-windows-file-caching-tip-tips-tricks-2130881-0.html
Thanks
I tried using a ramdisk from imdisk, because the above article
was just for caching network drives to your local disk. The
first set of times are from the ssd, the second from the ram
disk, and both are about the same. So I guess win7 is caching
these file reads already.
I got imdisk for the ramdisk here
http://www.ltr-data.se/opencode.html/#ImDisk
These are the times for the imdisk reads (still executing from G
hard drive , but reading from F ram disk)
G:\d\a7\a7\Release>wctest f:\al*.txt
finished wcp_nothing! time: 1 ms
finished wcp_whole_file! time: 31 ms
finished wcp_byLine! time: 525 ms
finished wcp_byChunk! time: 22 ms
finished wcp_lcByChunk! time: 33 ms
finished wcp_lcDcharByChunk! time: 30 ms
finished wcp_lcRegex! time: 141 ms
finished wcp_lcCtRegex! time: 104 ms
finished wcp_lcStdAlgoCount! time: 139 ms
finished wcp_lcChar! time: 37 ms
finished wcp_wcPointer! time: 121 ms
finished wcp_wcCtRegex! time: 1269 ms
finished wcp_wcRegex! time: 2908 ms
finished wcp_wcRegex2! time: 2693 ms
finished wcp_wcSlices! time: 179 ms
finished wcp_wcStdAscii! time: 222 ms
This is reading from the ssd Intel 510 series 120GB
G:\d\a7\a7\Release>wctest h:\al*.txt
finished wcp_nothing! time: 1 ms
finished wcp_whole_file! time: 32 ms
finished wcp_byLine! time: 518 ms
finished wcp_byChunk! time: 23 ms
finished wcp_lcByChunk! time: 33 ms
finished wcp_lcDcharByChunk! time: 31 ms
finished wcp_lcRegex! time: 159 ms
finished wcp_lcCtRegex! time: 89 ms
finished wcp_lcStdAlgoCount! time: 144 ms
finished wcp_lcChar! time: 34 ms
finished wcp_wcPointer! time: 118 ms
finished wcp_wcCtRegex! time: 1273 ms
finished wcp_wcRegex! time: 2889 ms
finished wcp_wcRegex2! time: 2688 ms
finished wcp_wcSlices! time: 175 ms
finished wcp_wcStdAscii! time: 220 ms
I added the source and the test text files on github
https://github.com/jnorwood/wc_test
