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

["Marco Costalba" <mcostalba@gmail.com>]

On 11/19/06, Marco Costalba <mcostalba@gmail.com> wrote:
>
> When finished I will do additional cold chache (reboot) tests.
>

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)           = ?