Re: [WISH] Store also tag dereferences in packed-refs

On 11/19/06, Marco Costalba <mcostalba@gmail.com> wrote:

Previous delay was not reproduced. This time I tested also with git show-ref -d (dereferencing tags), always with cold-cache.

It does not seems there are strange delays, but total time it's high (very I/O bound)

- LINUX TREE

$ pwd /git/linux-2.6

$ time strace -o tracefile -Ttt git show-ref -d >> /dev/null 0.02user 0.01system 0:02.39elapsed 1%CPU (0avgtext+0avgdata 0maxresident)k 0inputs+0outputs (127major+894minor)pagefaults 0swaps

$ grep -v ' <0.0[012]' tracefile >> tracefile_slowest.txt $ cat tracefile_slowest.txt 20:51:49.695511 execve("/home/marco/bin/git", ["git", "show-ref", "-d"], [/* 78 vars */]) = 0 <0.065006> 20:51:49.946258 open(".git/objects/info/alternates", O_RDONLY) = -1 ENOENT (No such file or directory) <0.091447> 20:51:50.070555 stat64(".git/objects/e0/30f8294a5b9f8179dae10cdbf9dcf32aa64110", {st_mode=S_IFREG|0444, st_size=284, ...}) = 0 <0.037669> 20:51:51.822469 stat64(".git/objects/7a/9d289b6650bf78df77ab463bedc2919df89833", {st_mode=S_IFREG|0444, st_size=285, ...}) = 0 <0.048868> 20:51:51.930582 stat64(".git/objects/80/c218812786f619c9a1ce50d0e7c32c7afde4de", {st_mode=S_IFREG|0444, st_size=210, ...}) = 0 <0.030057> 20:51:51.981951 stat64(".git/objects/44/597f65f6af3c692560a639f61d25398d13d1b6", {st_mode=S_IFREG|0444, st_size=249, ...}) = 0 <0.037440> 20:51:52.023469 exit_group(0) = ?

- GIT TREE

$cd /home/marco/programmi/git $ time strace -o tracefile -Ttt git show-ref -d >> /dev/null 0.04user 0.04system 0:02.47elapsed 3%CPU (0avgtext+0avgdata 0maxresident)k 0inputs+0outputs (91major+794minor)pagefaults 0swaps

$ grep -v ' <0.0[012]' tracefile >> tracefile_slowest.txt $ cat tracefile_slowest.txt 20:55:04.844584 stat64(".git/objects/d0/f877fb601ac0076fd69ec4f48f71f9247771c8", {st_mode=S_IFREG|0444, st_size=190, ...}) = 0 <0.046100> 20:55:04.944839 stat64(".git/objects/e2/67c2f6f0784e242883b7d3fe5f36ef63d6950d", {st_mode=S_IFREG|0444, st_size=179, ...}) = 0 <0.033536> 20:55:05.057966 stat64(".git/objects/41/292ddd37202ff6dce34986c87a6000c5d3fbfa", {st_mode=S_IFREG|0444, st_size=180, ...}) = 0 <0.072937> 20:55:05.432107 stat64(".git/objects/7d/09fbe4ab7f080a8f8f5dcef7e0f3edf5e26019", {st_mode=S_IFREG|0444, st_size=396, ...}) = 0 <0.035952> 20:55:05.592877 stat64(".git/objects/92/d7605b6d9312a29efa30b1baa4d7c880a0be41", {st_mode=S_IFREG|0444, st_size=280, ...}) = 0 <0.032139> 20:55:05.738173 stat64(".git/objects/05/56a11a0df6b4119e01aa77dfb795561e62eb34", {st_mode=S_IFREG|0444, st_size=557, ...}) = 0 <0.031572> 20:55:06.176786 stat64(".git/objects/88/3653babd8ee7ea23e6a5c392bb739348b1eb61", {st_mode=S_IFREG|0444, st_size=442, ...}) = 0 <0.030382> 20:55:06.549025 stat64(".git/objects/95/f1e36cc34e8738e5c431aac47d6fea18913db0", {st_mode=S_IFREG|0444, st_size=395, ...}) = 0 <0.031731> 20:55:06.844432 stat64(".git/objects/ba/f0bfcb4b335438e9359835f2c27cccf20e54a3", {st_mode=S_IFREG|0444, st_size=182, ...}) = 0 <0.033688> 20:55:06.922993 exit_group(0) = ?