Re: [LKP] [Btrfs] 3a8b36f3780: -62.6% fileio.requests_per_sec

[Huang Ying]

Hi, Filipe,

On Wed, 2015-03-18 at 10:05 +0000, Filipe Manana wrote:
[snip]

> Hi, thanks for this.
> 
> However this doesn't make sense to me.
> This commit only touches btrfs' fsync handler and the test uses sysbench
> without passing --file-fsync-freq to it, which means sysbench will never
> do fsyncs according to its man page (default for fsync frequency is 0).
> 
> Or maybe I missed something?

Sorry for late.

I checked source code of sysbench and found that the actual default
value of --file-fsync-freq is 100 instead of 0 in man page, as in the
following lines.

  {"file-fsync-freq", "do fsync() after this number of requests (0 - don't use fsync())",
   SB_ARG_TYPE_INT, "100"},

I double checked that via a debug patch to sysbench too.

Best Regards,
Huang, Ying


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