Re: [PATCH v2] new: Don't scan unchanged directories with no sub-directories

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+From: David Bremner <david@tethera.net>\r
+To: Austin Clements <amdragon@MIT.EDU>, notmuch@notmuchmail.org\r
+Subject: Re: [PATCH v2] new: Don't scan unchanged directories with no\r
+       sub-directories\r
+In-Reply-To: <1382650739-12438-1-git-send-email-amdragon@mit.edu>\r
+References: <20131024210837.GH20337@mit.edu>\r
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+Date: Fri, 25 Oct 2013 21:13:45 -0300\r
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+Austin Clements <amdragon@MIT.EDU> writes:\r
+\r
+> This can substantially reduce the cost of notmuch new in some\r
+> situations, such as when the file system cache is cold or when the\r
+> Maildir is on NFS.\r
+\r
+On my desktop at home (a core i7 950) with spinning rust disks (and lvm\r
+on luks) this patch yields about a 7% slowdown in the intial new perf\r
+test\r
+\r
+from\r
+\r
+                       Wall(s) Usr(s)  Sys(s)  Res(K)  In/Out(512B)\r
+  Initial notmuch new   579.60 348.86  14.26   217188  5330266/3501272\r
+\r
+to\r
+\r
+                       Wall(s) Usr(s)  Sys(s)  Res(K)  In/Out(512B)\r
+  Initial notmuch new   620.51 368.62  15.48   217156  5330354/3416456\r
+\r
+On an SSD I don't detect a significant different (<0.5% speedup)\r
+\r
+d\r