On 22 December 2014 at 15:01, Ivan Zhakov <i...@visualsvn.com> wrote: > On 17 July 2014 at 18:00, <stef...@apache.org> wrote: >> Author: stefan2 >> Date: Thu Jul 17 15:00:33 2014 >> New Revision: 1611380 >> >> URL: http://svn.apache.org/r1611380 >> Log: >> Work around for the poor performance of APR reader / writer locks on Windows. >> Basically, fall back to 1.7 code on Win32 by using a simple mutex. >> >> This resulted in a 35% increase in throughput for a 'null-export' over >> ra_serf from hot SVN caches with revprop caching enabled. OTOH, this may >> cost us some scalability with ra_svn on high-speed (>1Gb) networks. >> >> * subversion/libsvn_subr/cache-membuffer.c >> (USE_SIMPLE_MUTEX): New flag. Set depending on whether we need to fall >> back to a simple locking scheme. >> (svn_membuffer_t): Select lock type at compile time. >> (read_lock_cache, >> write_lock_cache, >> force_write_lock_cache, >> unlock_cache): Use the simple mutex lock when selected. >> (svn_cache__membuffer_cache_create): Initialize the correct lock type and >> disable the counter_mutex if >> redundant. >> >> Modified: >> subversion/trunk/subversion/libsvn_subr/cache-membuffer.c >> > [...] >> @@ -674,6 +712,12 @@ static svn_error_t * >> unlock_cache(svn_membuffer_t *cache, svn_error_t *err) >> { >> #if APR_HAS_THREADS >> +# if USE_SIMPLE_MUTEX >> + >> + return svn_mutex__unlock(cache->lock, SVN_NO_ERROR); >> + >> +# else >> + >> if (cache->lock) >> { >> apr_status_t status = apr_thread_rwlock_unlock(cache->lock); >> @@ -683,6 +727,8 @@ unlock_cache(svn_membuffer_t *cache, svn >> if (status) >> return svn_error_wrap_apr(status, _("Can't unlock cache mutex")); >> } >> + >> +# endif >> #endif >> return err; >> } > The provided ERR argument is ignored in USE_SIMPLE_MUTEX codepath. So > any error from cache serializer will be ignored and invalid result > will be used. > I've fixed this problem in r1647339 and another similar problem in r1647372.
-- Ivan Zhakov
