[fpc-devel] FPC/Lazarus Rebuild performance

Daniel danielfigueiredo at gmail.com
Fri Sep 10 18:16:43 CEST 2010

AFAIR the ATTO tool measures read and write bursts of single "files" X in size.

An interesting exercise is to transfer 1000 files to a USB memory
stick in 2 situations:

- Compacted in a single file, transfers at or near full USB speed.
- Spread out normally on a folder takes forever.

This happens because the time it takes to SWITCH between one file to
another is significant. Ending one operation (a single file transfer)
and begining another takes a time slice. Summing up all these start
and finish ops takes a significant time slice.

I guess this kind of behaviour is exactly what you're noticing. The
raw I/O transfer speed provided by your SSD is enough for your needs.
A faster channel won't help you. Some other factor is accounting for
your lags.

You can't really judge a storage medium just by a single benchmark
kind. The compiler will ask for your storage medium to seek files all
the time. Switching files all the time. This takes time. Much more
time than blazing through a single file like ATTO does.

On Fri, Sep 10, 2010 at 12:54, Jonas Maebe <jonas.maebe at elis.ugent.be> wrote:
> On 10 Sep 2010, at 17:43, Adem wrote:
>>   SSD: 103,060 ms (1 min 43 sec)
>> RAMDisk: 105,463 ms (1 min 46 sec)
>> This doesn't make sense. FPC/Lazarus compiles on the faster medium longer
>> (albeit only 3 sec.).
> Everything on your SSD is cached in RAM, so it's normal that both are about
> the same speed. The 3 seconds difference is probably just noise.
> Jonas
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