http://bugzilla.slf4j.org/show_bug.cgi?id=298
Summary: locks around logger maps inhibit concurrency
Product: SLF4J
Version: 1.7.x
Platform: All
OS/Version: All
Status: NEW
Severity: major
Priority: P1
Component: Implementations
AssignedTo: [email protected]
ReportedBy: [email protected]
I'm analyzing degraded performance in a new release of out web application.
The application has relatively high throughput (>4k requests/s). We're seeing
increased contention on the lock-guarded "loggerMap" in SLF4JLogFactory.
The change that introduced this contention is that some of the libraries we're
using (Spring, in this particular case) apparently have started creating Logger
instances in request-scoped objects in new versions, increasing the volume of
calls to SLF4JLogFactory.getInstance().
The top of the call stack of threads waiting for the lock in question looks
like shown below.
Given that SLF4J targets Java 5+, it seems that some of the util.concurrent
constructs could be used to make logger retrieval lock-free for the common
cases.
-----------
http-/0.0.0.0:8080-187 [BLOCKED] CPU time: 3s
org.apache.commons.logging.impl.SLF4JLogFactory.getInstance(String)
org.apache.commons.logging.impl.SLF4JLogFactory.getInstance(Class)
org.apache.commons.logging.LogFactory.getLog(Class)
org.springframework.util.ConcurrencyThrottleSupport.<init>()
org.springframework.core.task.SimpleAsyncTaskExecutor$ConcurrencyThrottleAdapter.<init>()
org.springframework.core.task.SimpleAsyncTaskExecutor$ConcurrencyThrottleAdapter.<init>(SimpleAsyncTaskExecutor$1)
org.springframework.core.task.SimpleAsyncTaskExecutor.<init>(String)
org.springframework.web.context.request.async.WebAsyncManager.<init>()
org.springframework.web.context.request.async.WebAsyncUtils.getAsyncManager(ServletRequest)
org.springframework.web.servlet.FrameworkServlet.processRequest(HttpServletRequest,
HttpServletResponse)
org.springframework.web.servlet.FrameworkServlet.doPost(HttpServletRequest,
HttpServletResponse)
javax.servlet.http.HttpServlet.service(HttpServletRequest, HttpServletResponse)
org.springframework.web.servlet.FrameworkServlet.service(HttpServletRequest,
HttpServletResponse)
javax.servlet.http.HttpServlet.service(ServletRequest, ServletResponse)
org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ServletRequest,
ServletResponse)
org.apache.catalina.core.ApplicationFilterChain.doFilter(ServletRequest,
ServletResponse)
-----------
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