I tested Jussi's preallocation scheme:
( lseeking in 4096 increments + writing 4 bytes at the beginning of each block)
30secs von 80secs when doing plain write()s even when writing 1MB at time.
that means more than twice as fast.
But I still have my doubts that all blocks gets really allocated:
f
On Fri, 21 Apr 2000, Paul Barton-Davis wrote:
> >PS: Paul run it on your 10k rpm SCSI disk so that we can do some comparison.
>
> I hope you are ready for some *very* different numbers.
>
> /tmp/hdtest 500 async trunc
> SINGLE THREADED: 12.788 MByte/sec
> MULTI-THREADED: 12.788 MByte/sec
>
> /t
>./hdtest 500 async trunc
>SINGLE THREADED: 5.856 MByte/sec
>MULTI-THREADED: 6.096 MByte/sec
>
>./hdtest 500 async notrunc (rewrite to preallocated files)
>SINGLE THREADED: 4.040 MByte/sec
>MULTI-THREADED: 4.766 MByte/sec
>
>./hdtest 150 sync trunc
>
>SINGLE THREADED: 1.442 MByte/sec
>MULT
Hi, more realworld of writing / vs rewriting (without O_TRUNC) to files
performance:
I enchanced hdtest.c a bit in order to recognize the "notrunc" flag which opens
the file without O_TRUNC (you have to run a first test with "trunc" in order to
create the files, which are created in an interleav
On Thu, 20 Apr 2000, Stephen C. Tweedie wrote:
>much difference, and it may be the stick we need to beat Linus into
>believing that this change is really quite important.
The change is really quite important and it will return to be important as
it was importnat in 2.2.x when raid5 will work kee
