Re: [msysGit] [PATCH] MinGW readdir reimplementation to support d_type

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

 



Marius Storm-Olsen schrieb:
The original readdir implementation was fast, but didn't
support the d_type. This means that git would do additional
lstats for each entry, to figure out if the entry was a
directory or not. This unneedingly slowed down many
operations, since Windows API provides this information
directly when walking the directories.

By running this implementation on Moe's repo structure:
  mkdir bummer && cd bummer; for ((i=0;i<100;i++)); do
    mkdir $i && pushd $i;
      for ((j=0;j<1000;j++)); do echo "$j" >$j; done;
    popd;
  done

We see the following speedups:
  git add .
  -------------------
  old: 00:00:23(.087)
  new: 00:00:21(.512) 1.07x

  git status
  -------------------
  old: 00:00:03(.306)
  new: 00:00:01(.684) 1.96x

  git clean -dxf
  -------------------
  old: 00:00:01(.918)
  new: 00:00:00(.295) 6.50x

Well done!

+struct mingw_dirent
+{
+	long		d_ino;			/* Always zero. */
+	union {
+		unsigned short	d_reclen;	/* Always zero. */
+		unsigned char   d_type;		/* Reimplementation adds this */
+	};

VERY sneaky! I was wondering why you could get away without replacing opendir and closedir, and why you still defined a replacement mingw_DIR that contains the replacement mingw_dirent, until I noticed this unnamed union.

Since we don't use d_reclen anywhere in the code, wouldn't you get away with

#define d_type d_reclen

unless the type (short vs. char) makes a difference. Or would you say that doing that would be even more sneaky?

+	unsigned short	d_namlen;		/* Length of name in d_name. */
+	char		d_name[FILENAME_MAX];	/* File name. */
+};
+#define dirent mingw_dirent
+#define readdir(x) mingw_readdir(x)
+#endif // !NO_MINGW_REPLACE_READDIR

-- Hannes

--
To unsubscribe from this list: send the line "unsubscribe git" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html

[Index of Archives]     [Linux Kernel Development]     [Gcc Help]     [IETF Annouce]     [DCCP]     [Netdev]     [Networking]     [Security]     [V4L]     [Bugtraq]     [Yosemite]     [MIPS Linux]     [ARM Linux]     [Linux Security]     [Linux RAID]     [Linux SCSI]     [Fedora Users]