[Dovecot] Maildir dirty syncs

[Timo Sirainen]

On Wed, 2009-03-04 at 19:30 -0500, Timo Sirainen wrote:
> http://dovecot.org/patches/1.1/maildir-dirty-syncs.diff
..
> I'd be interested in hearing how large performance benefits it gives, if
> any. 

Anyone?

I did a couple of small unrealistic tests with imaptest. With small
mailboxes it shows no difference. With larger mailboxes it seemed to be
about 25% faster:

N=old behavior, Y=dirty syncs

imaptest logout=0 secs=30 logout=0 msgs=1000 delete=10 expunge=10
  Logi List Stat Sele Fetc Fet2 Stor Dele Expu Appe Logo 
  100%  50%  50% 100% 100% 100%  50%  10%  10% 100%  10% 
                            30%                  5%      
N:  10 2122 2112   10 4146 5947 2045  334  411 2344 
Y:  10 2911 2899   10 5761 8194 2758  444  578 3629 

imaptest logout=0 secs=30 logout=0 msgs=10000 delete=10 expunge=10
  Logi List Stat Sele Fetc Fet2 Stor Dele Expu Appe Logo 
  100%  50%  50% 100% 100% 100%  50%  10%  10% 100%  10% 
                            30%                  5%      
N:  10 1553 1555   10 3129 4514 1548  245  336 3132  --> 2717 msgs in maildir
Y:  10 2157 2109   10 4189 6053 2035  310  441 4190  --> 3673 msgs in maildir

Although if the clients are disconnecting often, there's not much of an
improvement:

imaptest box=lols logout=0 secs=30 logout=10 msgs=1000 delete=10 expunge=10
  Logi List Stat Sele Fetc Fet2 Stor Dele Expu Appe Logo 
  100%  50%  50% 100% 100% 100%  50%  10%  10% 100%  10% 
			    30%                  5%      
N: 502 2779 2837  502 5627 7996 2776  455  604 2411 1004 
Y: 593 2909 2975  593 5892 8526 2895  467  559 2491 1186 

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