Re: svn commit: r1078357 - in /subversion/trunk: ./ build.conf subversion/libsvn_fs_fs/caching.c subversion/libsvn_fs_fs/fs.h subversion/libsvn_fs_fs/fs_fs.c subversion/svnadmin/main.c

stefan2_at_apache.org writes:

> Author: stefan2
> Date: Sat Mar 5 21:18:33 2011
> New Revision: 1078357

> Modified: subversion/trunk/subversion/svnadmin/main.c
> URL: http://svn.apache.org/viewvc/subversion/trunk/subversion/svnadmin/main.c?rev=1078357&r1=1078356&r2=1078357&view=diff
> ==============================================================================
> --- subversion/trunk/subversion/svnadmin/main.c (original)
> +++ subversion/trunk/subversion/svnadmin/main.c Sat Mar 5 21:18:33 2011
> @@ -290,6 +290,11 @@ static const apr_getopt_option_t options
> N_("use format compatible with Subversion versions\n"
> " earlier than 1.7")},
>
> + {"memory-cache-size", 'M', 1,
> + N_("size of the extra in-memory cache in MB used to\n"
> + " minimize redundant operations. Default: 256.\n"
> + " [used for FSFS repositories only]")},
> +
> {NULL}
> };

>
> @@ -1650,6 +1656,7 @@ main(int argc, const char *argv[])
> /* Initialize opt_state. */
> opt_state.start_revision.kind = svn_opt_revision_unspecified;
> opt_state.end_revision.kind = svn_opt_revision_unspecified;
> + opt_state.memory_cache_size = 0x10000000; /* 256 MB */

256MB is a magic number. How was its value determined?

It causes the regression tests to fail on machines with 2GB of memory
when the tests are run in parallel, as they cannot allocate 10*256MB.

There appears to be a significant overhead setting up the cache.
Setting the magic number to 16MB makes the tests noticeably faster,
setting it to 1MB makes the tests faster still.

-- 
Philip