From 4f382f75b541e7a7b3b668f617041fbb058938fe Mon Sep 17 00:00:00 2001 From: Bartosz Taudul Date: Tue, 22 Sep 2020 19:03:01 +0200 Subject: [PATCH] Update manual. --- manual/tracy.tex | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/manual/tracy.tex b/manual/tracy.tex index 540fed4e..08b053b9 100644 --- a/manual/tracy.tex +++ b/manual/tracy.tex @@ -146,7 +146,7 @@ One microsecond ($\frac{1}{1000}$ of a millisecond) in our comparison equals to And finally, one nanosecond ($\frac{1}{1000}$ of a microsecond) would be one nanometer. The modern microprocessor transistor gate, the width of DNA helix, or the thickness of a cell membrane are in the range of 5~\si{\nano\metre}. In one~\si{\nano\second} the light can travel only 30~\si{\centi\meter}. -Tracy can achieve single-digit nanosecond measurement resolution, due to usage of hardware timing mechanisms on the x86 and ARM architectures\footnote{In both 32 and 64~bit variants. On x86 Tracy requires a modern version of the \texttt{rdtsc} instruction (Sandy Bridge and later). On ARM-based systems Tracy will try to use the timer register (\textasciitilde 40 \si{\nano\second} resolution). If it fails (due to kernel configuration), Tracy falls back to system provided timer, which can range in resolution from 250 \si{\nano\second} to 1 \si{\micro\second}.}. Other profilers may rely on the timers provided by operating system, which do have significantly reduced resolution (about 300~\si{\nano\second} -- 1~\si{\micro\second}). This is enough to hide the subtle impact of cache access optimization, etc. +Tracy can achieve single-digit nanosecond measurement resolution, due to usage of hardware timing mechanisms on the x86 and ARM architectures\footnote{In both 32 and 64~bit variants. On x86 Tracy requires a modern version of the \texttt{rdtsc} instruction (Sandy Bridge and later). Note that resolution of Time Stamp Counter readings may depend on the actual used hardware and its design decisions related to how TSC synchronization is handled between different CPU sockets, etc. On ARM-based systems Tracy will try to use the timer register (\textasciitilde 40 \si{\nano\second} resolution). If it fails (due to kernel configuration), Tracy falls back to system provided timer, which can range in resolution from 250 \si{\nano\second} to 1 \si{\micro\second}.}. Other profilers may rely on the timers provided by operating system, which do have significantly reduced resolution (about 300~\si{\nano\second} -- 1~\si{\micro\second}). This is enough to hide the subtle impact of cache access optimization, etc. \subsubsection{Timer accuracy}