On Thu, May 21, 2015 at 10:53 PM, <steve.nor...@thomsonreuters.com> wrote: > On Thu, May 21, 2015a at 9:31 PM, Duy Nguyen [mailto:pclo...@gmail.com], did > scribble: >> > In case an object is not found pack directory is re-read again, which >> > might cause some increased load on nfs. >> > has_sha1_file() not finding the object should not happen often.. >> >> That last statement is probably very wrong, but I have no time to test this >> now. In index-pack, there is a has_sha1_file() for file collision test. That >> call >> on a fresh clone would fail for _every_ object in the >> (new) pack and the cost of reprepare pack files could be sky high... > > Confirmed with bisect that it is that commit: > > ~/git $ git bisect bad > 45e8a7487339c0f0ea28244ef06851308d07387c is the first bad commit > commit 45e8a7487339c0f0ea28244ef06851308d07387c > Author: Jeff King <p...@peff.net> > Date: Fri Aug 30 15:14:13 2013 -0400 > > I have an strace for that build but it is 153 megabytes so I probably > shouldn't attach, but the call summary is below: > > % time seconds usecs/call calls errors syscall > ------ ----------- ----------- --------- --------- ---------------- > 93.71 39.670084 103 386835 2171 futex > 3.16 1.338572 7 190550 181 open > 1.56 0.658786 18 37450 3 read > 0.62 0.262740 2 141390 pread > 0.41 0.171526 5 37313 9 write > 0.18 0.076166 0 188859 188835 access > 0.11 0.047941 0 374712 getdents > 0.11 0.045174 11 4067 3910 lstat > 0.06 0.023630 0 190425 close > 0.04 0.017995 6 2975 1 fstat > 0.02 0.007668 1917 4 wait4 > 0.01 0.004150 1 5065 madvise > 0.01 0.003548 0 16090 8 recvfrom > 0.00 0.001872 0 8048 select > 0.00 0.001870 11 173 1 mkdir > 0.00 0.000872 0 8055 poll > 0.00 0.000262 22 12 12 readlink > 0.00 0.000185 0 1217 1146 stat > 0.00 0.000158 0 457 mprotect > 0.00 0.000074 0 298 mmap > 0.00 0.000069 1 109 8 rt_sigreturn > 0.00 0.000047 0 159 brk > 0.00 0.000021 1 17 getcwd > 0.00 0.000000 0 42 3 lseek > 0.00 0.000000 0 92 munmap > 0.00 0.000000 0 35 rt_sigaction > 0.00 0.000000 0 9 rt_sigprocmask > 0.00 0.000000 0 8 3 ioctl > 0.00 0.000000 0 11 pipe > 0.00 0.000000 0 3 dup > 0.00 0.000000 0 8 dup2 > 0.00 0.000000 0 6 setitimer > 0.00 0.000000 0 11 1 socket > 0.00 0.000000 0 8 7 connect > 0.00 0.000000 0 8 sendto > 0.00 0.000000 0 2 recvmsg > 0.00 0.000000 0 1 bind > 0.00 0.000000 0 1 getsockname > 0.00 0.000000 0 3 1 getpeername > 0.00 0.000000 0 2 setsockopt > 0.00 0.000000 0 2 getsockopt > 0.00 0.000000 0 8 clone > 0.00 0.000000 0 5 execve > 0.00 0.000000 0 3 uname > 0.00 0.000000 0 100 fcntl > 0.00 0.000000 0 2 fsync > 0.00 0.000000 0 13 chdir > 0.00 0.000000 0 14 rename > 0.00 0.000000 0 2 link > 0.00 0.000000 0 5 unlink > 0.00 0.000000 0 2 symlink > 0.00 0.000000 0 9 chmod > 0.00 0.000000 0 6 getrlimit > 0.00 0.000000 0 2 sysinfo > 0.00 0.000000 0 8 getuid > 0.00 0.000000 0 1 statfs > 0.00 0.000000 0 5 arch_prctl > 0.00 0.000000 0 1 gettid > 0.00 0.000000 0 5 set_tid_address > 0.00 0.000000 0 13 set_robust_list > ------ ----------- ----------- --------- --------- ---------------- > 100.00 42.333410 1594736 196300 total > > Is there anything else I can provide or test?
In builtin/index-pack.c, replace the line "collision_test_needed = has_sha1_file(sha1);" with "collision_test_needed = 0;". Security is compromised but for this test it should be ok. Then clone again. I hope the new number gets down close to v1.8.4.1. -- Duy -- To unsubscribe from this list: send the line "unsubscribe git" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
