From 2e418f24fa721ab8aff39af8f6f0efee3ada61bf Mon Sep 17 00:00:00 2001 From: Bartosz Taudul Date: Tue, 7 Apr 2020 22:17:24 +0200 Subject: [PATCH] Update manual. --- manual/tracy.tex | 4 ++++ 1 file changed, 4 insertions(+) diff --git a/manual/tracy.tex b/manual/tracy.tex index 5e18ae09..80a1364b 100644 --- a/manual/tracy.tex +++ b/manual/tracy.tex @@ -415,6 +415,10 @@ mount -o remount,hidepid=0 /proc The first command will allow access to system CPU statistics. The second one will allow inspection of foreign processes (which is required for context switch capture). \emph{Be sure that you are fully aware of the consequences of making these changes.} +\paragraph{Cloud service providers} + +In some cases you actually don't own the hardware, but lend it from someone else. In such circumstances you might be running inside a virtual machine, which may be configured to prohibit you from using the bare metal facilities needed by Tracy\footnote{Or you might just be using a quite old CPU, which doesn't have support for required features.}. One example of such limitation would be lack of access to a reliable time stamp register readings, which will prevent the application from starting with either 'CPU doesn't support RDTSCP instruction' or 'CPU doesn't support invariant TSC' error message. If you are using Windows, you may workaround this issue by rebuilding the profiled application with the \texttt{TRACY\_TIMER\_QPC} macro, but be aware that it will severely lower the resolution of timer readings. + \subsubsection{Changing network port} Network communication between the client and the server by default is performed using network port 8086. The profiling session utilizes the TCP protocol and client broadcasts are done over UDP.