Re: Disk-based logger - write pretouch

Il giorno lunedì 10 luglio 2017 20:41:23 UTC+2, Roman Leventov ha scritto: > > On 10 July 2017 at 13:21, Martin Thompson > wrote: > >> Are you running recent MacOS with APFS which supports sparse files? >> > > If this is of any interest, my OS version is > > Darwin

Re: Disk-based logger - write pretouch

I would be interested to test it with zfs, it might even be harmful On Mon, Jul 10, 2017 at 11:55 PM, Michael Barker wrote: > From our own experience with journaling the benefits of pre-touching files > depends on the file system used. When ended up using XFS and threw away

Re: Disk-based logger - write pretouch

A few suggestions: 1) have you tried just reading the data in the prefaulting code, instead of dirtying it with a dummy write? Since this is a disk backed mapping, it should page fault and map the underlying file data (rather than mapping to a zero page, e.g.). At a high rate of dirtying, this

Re: Disk-based logger - write pretouch

Are you running recent MacOS with APFS which supports sparse files? Linux supports sparse files but not all OSs do. You need to run Linux to get reasonable profiling information from the OS that is generally applicable. Then you can use nice tools like those from Brendan Gregg.