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<span style="color: rgb(12, 100, 192);">Replied inline.</span></div>
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<div id="divRplyFwdMsg" dir="ltr"><font face="Calibri, sans-serif" color="#000000" style="font-size:11pt"><b>From:</b> 徐青青 <xuqingqing.0729@bytedance.com><br>
<b>Sent:</b> Tuesday, November 2, 2021 2:16 AM<br>
<b>To:</b> Lei Wang <wlei@fb.com><br>
<b>Cc:</b> via llvm-dev <llvm-dev@lists.llvm.org>; Hongtao Yu <hoy@fb.com>; Wenlei He <wenlei@fb.com>; compiler <compiler@bytedance.com><br>
<b>Subject:</b> Re: [External] Re: [llvm-dev] Performance benefits shown in [RFC: CSSPGO with Pseudo-Instrumentation] can't be reproduced.</font>
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<div class="" dir="auto"><span>Can you send the results for each benchmark in SpecCPU2006 in detail instead of Geometric? I can compare your results with SpecCPU2017 because there are some common benchmarks in SpecCPU2006 and
</span><span class="x_backgroundcolor x_fontweight x_fontsize x_fontcolor" style="background-color:rgba(0,0,0,0); font-weight:400; font-size:14px; color:#1f2329">SpecCPU2017.</span></div>
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<div class="" dir="auto"><span class="x_fontfamily x_backgroundcolor x_fontweight x_fontsize x_fontcolor" style="font-family:Calibri,sans-serif; background-color:rgb(255,255,255); font-weight:400; font-size:14.6667px; color:#1f2329">And in patch
</span><span class="x_outer-u-container"><span class="x_hyperlink-href:https://reviews.llvm.org/D110081 x_u x_fontfamily x_backgroundcolor x_fontweight x_fontsize" style="font-family:Calibri,sans-serif; background-color:rgb(255,255,255); font-weight:400; font-size:14.6667px"><a href="https://reviews.llvm.org/D110081" rel="noopener" target="_blank" style="color:rgb(51,112,255); text-decoration:none"><u><span></span></u></a><u><a href="https://reviews.llvm.org/D110081" target="_blank">https://reviews.llvm.org/D110081</a></u></span></span></div>
<div class="" dir="auto"><span>I also have questions:</span></div>
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<li start="1" class="" style="padding-left:0px;line-height:1.6;vertical-align:-4px;list-style-type:decimal">
<span style="display:none"></span><span class="x_pocket-ignore x_pocket-ignore-faketext"></span><span>Have you seen the compilation error when you use CSSPGO in SpecCPU2006? I
</span><span class=""><span class="x_grammar-check-c186b643-76c7-46ad-810a-c185aab53ae8 x_gcheck">seen</span></span><span> the error in SpecCPU2017-502.gcc_r. This benchmark also exists in SpecCPU2006.</span></li></ol>
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<div><span><span dir="auto" style="margin:0px;background-color:rgb(255, 255, 255)"><span style="margin:0px;font-size:12pt;line-height:normal;font-family:Calibri, Arial, Helvetica, sans-serif;color:rgb(12, 100, 192)">What compilation error did you see?</span></span><br>
</span></div>
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</span></div>
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<li start="2" class="" style="padding-left:0px;line-height:1.6;vertical-align:-4px;list-style-type:decimal">
<span style="display:none"></span><span class="x_pocket-ignore x_pocket-ignore-faketext"></span><span>About the fix, we may have better choice.</span><span class="x_i x_fontfamily x_backgroundcolor x_fontcolor" style="font-family:Lato,Helvetica,Arial,sans-serif; background-color:rgb(248,249,252); color:rgb(70,76,92)"><i>
About the question: </i></span><span class="x_i x_fontfamily x_backgroundcolor x_fontweight x_fontsize x_fontcolor" style="font-family:Lato,Helvetica,Arial,sans-serif; background-color:rgb(248,249,252); font-weight:400; font-size:13px; color:rgb(70,76,92)"><i>Can
we potentially lose contexts when an invalid line offset is one of the frames? Like A:-1 @ B:2 @ C:3, without this change, we could still have samples for B:2 @ C:3. But I think that's rare.</i></span></li></ol>
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<ul class="x_list-indent1" style="margin:0px; padding:0px; list-style-type:none; margin-left:21px">
<li style="display:block"><span class="x_fontfamily x_backgroundcolor x_fontweight x_fontsize x_fontcolor" style="font-family:Lato,Helvetica,Arial,sans-serif; background-color:rgb(255,255,255); font-weight:400; font-size:13px; color:rgb(146,150,157)">You say
that: you haven't seen those cases, it seems it only happened for leaf frame. Even
</span><span class=""><span class="x_grammar-check-9c2260b7-1ab7-4863-a1ea-fb5af5ac40b4 x_gcheck x_fontfamily x_backgroundcolor x_fontweight x_fontsize x_fontcolor" style="font-family:Lato,Helvetica,Arial,sans-serif; background-color:rgb(255,255,255); font-weight:400; font-size:13px; color:rgb(146,150,157)">it</span></span><span class="x_fontfamily x_backgroundcolor x_fontweight x_fontsize x_fontcolor" style="font-family:Lato,Helvetica,Arial,sans-serif; background-color:rgb(255,255,255); font-weight:400; font-size:13px; color:rgb(146,150,157)">
can be leaf call, there </span><span class=""><span class="x_grammar-check-b5e1c5a5-7145-4e79-a64e-5e2af88c3917 x_gcheck x_fontfamily x_backgroundcolor x_fontweight x_fontsize x_fontcolor" style="font-family:Lato,Helvetica,Arial,sans-serif; background-color:rgb(255,255,255); font-weight:400; font-size:13px; color:rgb(146,150,157)">is</span></span><span class="x_fontfamily x_backgroundcolor x_fontweight x_fontsize x_fontcolor" style="font-family:Lato,Helvetica,Arial,sans-serif; background-color:rgb(255,255,255); font-weight:400; font-size:13px; color:rgb(146,150,157)">
no samples hit the callee. </span><span class=""><span class="x_grammar-check-b15b064a-426d-415c-ba6b-f47e0c737d1b x_gcheck x_fontfamily x_backgroundcolor x_fontweight x_fontsize x_fontcolor" style="font-family:Lato,Helvetica,Arial,sans-serif; background-color:rgb(255,255,255); font-weight:400; font-size:13px; color:rgb(146,150,157)">you</span></span><span class="x_fontfamily x_backgroundcolor x_fontweight x_fontsize x_fontcolor" style="font-family:Lato,Helvetica,Arial,sans-serif; background-color:rgb(255,255,255); font-weight:400; font-size:13px; color:rgb(146,150,157)">
can add a warning on the non-leaf frame invalid line of stack address.</span></li></ul>
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<ul class="x_list-indent1" style="margin:0px; padding:0px; list-style-type:none; margin-left:21px">
<li style="display:block"><span class="x_fontfamily x_backgroundcolor x_fontweight x_fontsize x_fontcolor" style="font-family:Lato,Helvetica,Arial,sans-serif; background-color:rgb(255,255,255); font-weight:400; font-size:13px; color:rgb(0,0,0)">As for me, I
have seen</span><span class="x_grammar-check-ignore x_fontfamily x_backgroundcolor x_fontweight x_fontsize x_fontcolor" style="font-family:Lato,Helvetica,Arial,sans-serif; background-color:rgb(255,255,255); font-weight:400; font-size:13px; color:rgb(0,0,0)">
the</span><span class="x_fontfamily x_backgroundcolor x_fontweight x_fontsize x_fontcolor" style="font-family:Lato,Helvetica,Arial,sans-serif; background-color:rgb(255,255,255); font-weight:400; font-size:13px; color:rgb(0,0,0)"> cases that happened for non-leaf
frame. And if you filter out such callstack, the number of samples will decrease sharply. I haven't use the llvm-master successfully. After that I expect to show you.</span></li></ul>
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<div class="" dir="auto"><span style="font-size: 12pt; line-height: normal; color: rgb(12, 100, 192);">For the case like </span><span style="font-size: 12pt; line-height: normal; color: rgb(12, 100, 192);"><i style="color: rgb(70, 76, 92); font-family: Lato, Helvetica, Arial, sans-serif; text-align: left; line-height: normal;">A:-1
@ B:2 @ C:3, </i></span><i style="color:rgb(70, 76, 92);font-family:Lato, Helvetica, Arial, sans-serif;font-size:13px;text-align:left"><span style="color: rgb(12, 100, 192); font-family: Calibri, Arial, Helvetica, sans-serif; font-size: 12pt; font-style: normal; text-align: start; background-color: rgb(255, 255, 255); display: inline !important; line-height: normal;">see
the call stack will be truncated to </span><span style="color: rgb(12, 100, 192); font-family: Calibri, Arial, Helvetica, sans-serif; font-size: 12pt; font-style: normal; text-align: start; background-color: rgb(255, 255, 255); display: inline !important; line-height: normal;"><i style="background-color: rgb(255, 255, 255); color: rgb(70, 76, 92); font-family: Lato, Helvetica, Arial, sans-serif; text-align: left; line-height: normal;">B:2
@ C:3,</i></span><span style="color: rgb(12, 100, 192); font-family: Calibri, Arial, Helvetica, sans-serif; font-size: 12pt; font-style: normal; text-align: start; background-color: rgb(255, 255, 255); display: inline !important; line-height: normal;">. As
a result, the compiler will no longer be able to inline every function into A. The number of samples, in terms of LBR samples, will still be kept. </span></i></div>
<div class="" dir="auto"><i style="color:rgb(70, 76, 92);font-family:Lato, Helvetica, Arial, sans-serif;font-size:13px;text-align:left"><span style="color:rgb(12, 100, 192);font-family:Calibri, Arial, Helvetica, sans-serif;font-size:16px;font-style:normal;text-align:start;background-color:rgb(255, 255, 255);display:inline !important"><br>
</span></i></div>
<div class="" dir="auto"><i style="color:rgb(70, 76, 92);font-family:Lato, Helvetica, Arial, sans-serif;font-size:13px;text-align:left"><span style="color: rgb(12, 100, 192); font-family: Calibri, Arial, Helvetica, sans-serif; font-size: 12pt; font-style: normal; text-align: start; background-color: rgb(255, 255, 255); display: inline !important; line-height: normal;">There
is a warning emitted for that. Please see </span><span style="color:rgb(12, 100, 192);font-family:Calibri, Arial, Helvetica, sans-serif;font-size:16px;font-style:normal;text-align:start;background-color:rgb(255, 255, 255);display:inline !important"><a href="https://github.com/llvm/llvm-project/blob/main/llvm/tools/llvm-profgen/PerfReader.cpp#L436-L437" id="LPNoLPOWALinkPreview"><span style="font-size: 12pt; line-height: normal; color: rgb(12, 100, 192);">https://github.com/llvm/llvm-project/blob/main/llvm/tools/llvm-profgen/PerfReader.cpp#L436-L437</span></a></span><span style="color: rgb(12, 100, 192); font-family: Calibri, Arial, Helvetica, sans-serif; font-size: 12pt; font-style: normal; text-align: start; background-color: rgb(255, 255, 255); display: inline !important; line-height: normal;">.
It may not be in the 12.x branch.</span></i></div>
<div class="" dir="auto"><i style="color:rgb(70, 76, 92);font-family:Lato, Helvetica, Arial, sans-serif;font-size:13px;text-align:left"><span style="color:rgb(12, 100, 192);font-family:Calibri, Arial, Helvetica, sans-serif;font-size:16px;font-style:normal;text-align:start;background-color:rgb(255, 255, 255);display:inline !important"><br>
</span></i></div>
<div class="" dir="auto"><i style="color:rgb(70, 76, 92);font-family:Lato, Helvetica, Arial, sans-serif;font-size:13px;text-align:left"><span style="color: rgb(12, 100, 192); font-family: Calibri, Arial, Helvetica, sans-serif; font-size: 12pt; font-style: normal; text-align: start; background-color: rgb(255, 255, 255); display: inline !important; line-height: normal;">We
noticed a compiler optimization, aka, tail merge optimization, can cause such truncated stack cases. You may want to try turning it off with -</span></i><span style="color: rgb(12, 100, 192); font-size: 12pt; line-height: normal;">enable-tail-merge=0.</span></div>
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<div class="" dir="auto"><span class="x_fontfamily x_backgroundcolor x_fontweight x_fontsize x_fontcolor" style="background-color:rgb(255,255,255); font-weight:400; font-size:14px; color:rgb(43,47,54)">If possible, I look forward to a voice conference with
you if </span><span class="x_grammar-check-ignore x_fontfamily x_backgroundcolor x_fontweight x_fontsize x_fontcolor" style="background-color:rgb(255,255,255); font-weight:400; font-size:14px; color:rgb(43,47,54)">you are</span><span class="x_fontfamily x_backgroundcolor x_fontweight x_fontsize x_fontcolor" style="background-color:rgb(255,255,255); font-weight:400; font-size:14px; color:rgb(43,47,54)">
convenient at any time.</span></div>
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On Tue, Nov 2, 2021, 14:42 <<a href="mailto:xuqingqing.0729@bytedance.com" style="color:rgb(51,112,255)">xuqingqing.0729@bytedance.com</a>> wrote:</div>
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<blockquote itemscope="" itemtype="https://schemas.microsoft.com/QuotedText" style="border-left: 3px solid rgb(200, 200, 200); border-top-color: rgb(200, 200, 200); border-right-color: rgb(200, 200, 200); border-bottom-color: rgb(200, 200, 200); padding-left: 1ex; margin-left: 0.8ex; color: rgb(102, 102, 102);">
<div class="" dir="auto"><span>As you suggested, I remove </span><span class="x_fontfamily x_backgroundcolor x_fontweight x_fontsize x_fontcolor" style="font-family:Calibri,sans-serif; background-color:rgb(255,255,255); font-weight:400; font-size:14px; color:#000000">-fdebug-info-for-profiling
in first compiling process and add -flto in second compiling process for CSSPGO, -flto can bring great improvement.</span></div>
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<div dir="auto"><span style="font-family: Calibri, Arial, Helvetica, sans-serif; font-size: 12pt; line-height: normal; color: rgb(0, 0, 0);"></span><br>
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<div dir="auto"><span style="font-family: Calibri, Arial, Helvetica, sans-serif; font-size: 12pt; line-height: normal; color: rgb(12, 100, 192);">Would be better to apply lto to both pass1 and pass2.</span></div>
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</span></div>
<blockquote itemscope="" itemtype="https://schemas.microsoft.com/QuotedText" style="border-left: 3px solid rgb(200, 200, 200); border-top-color: rgb(200, 200, 200); border-right-color: rgb(200, 200, 200); border-bottom-color: rgb(200, 200, 200); padding-left: 1ex; margin-left: 0.8ex; color: rgb(102, 102, 102);">
<div class="" dir="auto"><span class="x_fontfamily x_backgroundcolor x_fontweight x_fontsize x_fontcolor" style="font-family:Calibri,sans-serif; background-color:rgb(255,255,255); font-weight:400; font-size:14px; color:#000000">To be fair, I also add -flto
in </span><span class="x_grammar-check-ignore x_fontfamily x_backgroundcolor x_fontweight x_fontsize x_fontcolor" style="font-family:Calibri,sans-serif; background-color:rgb(255,255,255); font-weight:400; font-size:14px; color:#000000">second</span><span class="x_fontfamily x_backgroundcolor x_fontweight x_fontsize x_fontcolor" style="font-family:Calibri,sans-serif; background-color:rgb(255,255,255); font-weight:400; font-size:14px; color:#000000">
compiling process for AutoFDO. The result </span><span class="x_grammar-check-ignore x_fontfamily x_backgroundcolor x_fontweight x_fontsize x_fontcolor" style="font-family:Calibri,sans-serif; background-color:rgb(255,255,255); font-weight:400; font-size:14px; color:#000000">shows</span><span class="x_fontfamily x_backgroundcolor x_fontweight x_fontsize x_fontcolor" style="font-family:Calibri,sans-serif; background-color:rgb(255,255,255); font-weight:400; font-size:14px; color:#000000">
that AutoFDO </span><span class="x_grammar-check-ignore x_fontfamily x_backgroundcolor x_fontweight x_fontsize x_fontcolor" style="font-family:Calibri,sans-serif; background-color:rgb(255,255,255); font-weight:400; font-size:14px; color:#000000">bring</span><span class="x_fontfamily x_backgroundcolor x_fontweight x_fontsize x_fontcolor" style="font-family:Calibri,sans-serif; background-color:rgb(255,255,255); font-weight:400; font-size:14px; color:#000000">
more performance benefits over CSSPGO (about 20% on SpecCPU2017's 523.xalancbmk_r).</span></div>
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</span></div>
<div class="" dir="auto"><font face="Calibri, sans-serif"><span style="color: rgb(12, 100, 192); font-size: 12pt; line-height: normal;">How about other benchmarks? xalanc is sort of unstable sometimes.</span></font></div>
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<blockquote itemscope="" itemtype="https://schemas.microsoft.com/QuotedText" style="border-left: 3px solid rgb(200, 200, 200); border-top-color: rgb(200, 200, 200); border-right-color: rgb(200, 200, 200); border-bottom-color: rgb(200, 200, 200); padding-left: 1ex; margin-left: 0.8ex; color: rgb(102, 102, 102);">
<div class="" dir="auto"><span class="x_fontfamily x_backgroundcolor x_fontweight x_fontsize x_fontcolor" style="font-family:Calibri,sans-serif; background-color:rgb(255,255,255); font-weight:400; font-size:14px; color:#000000">The version of llvm I used is
llvm-12. And your RFC is also based on llvm-12 according the time of RFC. Have I missed anything in the usage of CSSPGO? Is there any option for CSSPGO which I need to open manually? Could you please test the branch release/12.x and confirm the results to
help me to get performance benefits over AutoFDO?</span></div>
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<div class="" dir="auto"><span style="color: rgb(12, 100, 192); font-size: 12pt; line-height: normal;">Yes, there are other switches that can help boost the perfor</span><span style="color: rgb(12, 100, 192); font-size: 12pt; line-height: normal;">mance, such
as </span><span style="color: rgb(12, 100, 192); font-size: 12pt; line-height: normal;">-fno-omit-frame-pointer -mno-omit-leaf-frame-pointer -fno-optimize-sibling-calls -funique-internal-linkage-names. Note that with the main branch, </span><span style="background-color: rgb(255, 255, 255); display: inline !important; color: rgb(12, 100, 192); font-size: 12pt; line-height: normal;">-funique-internal-linkage-names
is auto</span><span style="background-color: rgb(255, 255, 255); display: inline !important; color: rgb(12, 100, 192); font-size: 12pt; line-height: normal;">matically turned on when -fpseudo-probe-for-profiling is on. </span></div>
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<div class="" dir="auto"><span style="color: rgb(12, 100, 192); font-size: 12pt; line-height: normal;">We've made a lot post-12.x improvements to csspgo and they are all in the main branch. Please give them a shot.</span></div>
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<div class="" dir="auto"><span class="x_fontfamily x_backgroundcolor x_fontweight x_fontsize x_fontcolor" style="font-family:Calibri,sans-serif; background-color:rgb(255,255,255); font-weight:400; font-size:14px; color:#000000">Thanks,</span></div>
<div class="" dir="auto"><span class="x_fontfamily x_backgroundcolor x_fontweight x_fontsize x_fontcolor" style="font-family:Calibri,sans-serif; background-color:rgb(255,255,255); font-weight:400; font-size:14px; color:#000000">Qingqing</span></div>
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<div class="" id="x_lark-mail-block-attr-163583532" style="color:rgb(143,149,158)">
On Sat, Oct 30, 2021, 04:53 <<a href="mailto:wlei@fb.com" rel="nofollow noopener noreferrer" style="color:rgb(51,112,255)">wlei@fb.com</a>> wrote:</div>
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<p class="x_MsoNormal" style="margin: 0in; font-size: 11pt; font-family: Calibri, sans-serif;">
BTW, regarding the issue in <a href="https://groups.google.com/g/llvm-dev/c/QJFIzk6bP1Y/m/8YlhrhXDAQAJ" rel="nofollow noopener noreferrer">https://groups.google.com/g/llvm-dev/c/QJFIzk6bP1Y/m/8YlhrhXDAQAJ</a>. (Sorry I overlooked the message)</p>
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<p class="x_MsoNormal" style="margin: 0in; font-size: 11pt; font-family: Calibri, sans-serif;">
We have a fix in <a href="https://reviews.llvm.org/D110081" rel="nofollow noopener noreferrer">https://reviews.llvm.org/D110081</a> which can filter out the negative LineOffset, you can have a try on latest llvm-profgen.</p>
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<p class="x_MsoNormal" style="margin: 0in; font-size: 11pt; font-family: Calibri, sans-serif;">
Thanks.</p>
<p class="x_MsoNormal" style="margin: 0in; font-size: 11pt; font-family: Calibri, sans-serif;">
Lei</p>
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<b><span style="font-size:12.0pt; color:black">From: </span></b><span style="font-size:12.0pt; color:black"><span>Hongtao Yu <<a href="mailto:hoy@fb.com" rel="nofollow noopener noreferrer">hoy@fb.com</a>></span><br>
<b>Date: </b>Friday, October 29, 2021 at 12:57 PM<br>
<b>To: </b><span>Wenlei He <<a href="mailto:wenlei@fb.com" rel="nofollow noopener noreferrer">wenlei@fb.com</a>>,
</span></span><span lang="ZH-CN" style="font-size:12pt; font-family:sans-serif; color:black">徐青青</span><span style="font-size:12.0pt; color:black"><span> <<a href="mailto:xuqingqing.0729@bytedance.com" rel="nofollow noopener noreferrer">xuqingqing.0729@bytedance.com</a>>,
via llvm-dev <<a href="mailto:llvm-dev@lists.llvm.org" rel="nofollow noopener noreferrer">llvm-dev@lists.llvm.org</a>></span><br>
<b>Cc: </b><span>Lei Wang <<a href="mailto:wlei@fb.com" rel="nofollow noopener noreferrer">wlei@fb.com</a>></span><br>
<b>Subject: </b>Re: [llvm-dev] Performance benefits shown in [RFC: CSSPGO with Pseudo-Instrumentation] can't be reproduced.</span></p>
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Please also be noted that in order to maximize the benefit from CSSPGO and its improved inlining, LTO mode is recommended. I suggest to try out -flto.</p>
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Thanks,</p>
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Hongtao</p>
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<b><span style="font-size:12.0pt; color:black">From: </span></b><span style="font-size:12.0pt; color:black"><span>Wenlei He <<a href="mailto:wenlei@fb.com" rel="nofollow noopener noreferrer">wenlei@fb.com</a>></span><br>
<b>Date: </b>Friday, October 29, 2021 at 12:49 PM<br>
<b>To: </b></span><span lang="ZH-CN" style="font-size:12pt; font-family:sans-serif; color:black">徐青青</span><span style="font-size:12.0pt; color:black"><span> <<a href="mailto:xuqingqing.0729@bytedance.com" rel="nofollow noopener noreferrer">xuqingqing.0729@bytedance.com</a>>,
via llvm-dev <<a href="mailto:llvm-dev@lists.llvm.org" rel="nofollow noopener noreferrer">llvm-dev@lists.llvm.org</a>></span><br>
<b>Cc: </b><span>Hongtao Yu <<a href="mailto:hoy@fb.com" rel="nofollow noopener noreferrer">hoy@fb.com</a>>, Lei Wang <<a href="mailto:wlei@fb.com" rel="nofollow noopener noreferrer">wlei@fb.com</a>></span><br>
<b>Subject: </b>Re: [llvm-dev] Performance benefits shown in [RFC: CSSPGO with Pseudo-Instrumentation] can't be reproduced.</span></p>
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For Spec2017, we’ve seen 1%+ CPU improvements on Broadwell hosts in the past. We use spec only for bringing up new technologies and we no longer tracks spec results now as we move towards production workload. Also note that the measurement was done on our internal
fork, with some internal patches. We’re still working on upstreaming some of them.
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For the setup, <span style="font-size:10.5pt; color:black; background:white">-fdebug-info-for-profiling needs to be removed.
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<span style="font-size:10.5pt; color:black; background:white">Thanks,</span><span style="font-size:10.5pt; background:white"></span></p>
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<span style="font-size:10.5pt; color:black; background:white">Wenlei</span><span style="font-size:10.5pt; background:white"></span></p>
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<b><span style="font-size:12.0pt; color:black">From: </span></b><span style="font-size:12.0pt; color:black"><span>llvm-dev <<a href="mailto:llvm-dev-bounces@lists.llvm.org" rel="nofollow noopener noreferrer">llvm-dev-bounces@lists.llvm.org</a>> on behalf of
</span></span><span lang="ZH-CN" style="font-size:12pt; font-family:sans-serif; color:black">徐青青</span><span style="font-size:12.0pt; color:black"><span> via llvm-dev <<a href="mailto:llvm-dev@lists.llvm.org" rel="nofollow noopener noreferrer">llvm-dev@lists.llvm.org</a>></span><br>
<b>Date: </b>Thursday, October 28, 2021 at 1:26 AM<br>
<b>To: </b><span>via llvm-dev <<a href="mailto:llvm-dev@lists.llvm.org" rel="nofollow noopener noreferrer">llvm-dev@lists.llvm.org</a>></span><br>
<b>Subject: </b>[llvm-dev] Performance benefits shown in [RFC: CSSPGO with Pseudo-Instrumentation] can't be reproduced.</span></p>
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<span style="font-size:10.5pt">Hi All,</span></p>
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<span style="font-size:10.5pt"> </span></p>
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<span style="font-size:10.5pt">I am using <b>CSSPGO with Pseudo-Instrumentation</b>. But I found that the performance benefits
<span class="x_grammar-check-ignore">shown</span> in <span class="x_hyperlink-hrefhttpsgroupsgooglecomgllvm-devc1p1rdybl93smijjcmus7awaj">
<a href="https://groups.google.com/g/llvm-dev/c/1p1rdYbL93s/m/iJjcmUS7AwAJ" rel="nofollow noopener noreferrer"><span style="color:#3370ff; text-decoration:none">[RFC: CSSPGO with Pseudo-Instrumentation]</span></a></span> <b><span style="color:black">can't be reproduced on Spec CPU 2017</span></b> based on
<b>llvm-12</b>. In RFC, results show that CSSPGO with Pseudo-Instrumentation achieves better performance over AutoFDO.</span></p>
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<span style="font-size:10.5pt"> </span></p>
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<span style="font-size:10.5pt">Here, I have two question:</span></p>
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<span style="font-size:10.5pt"><span style="">1.<span style="font:7.0pt "Times New Roman"">
</span></span></span><span class="x_pocket-ignore"><span style="font-size:10.5pt"></span></span><span style="font-size:10.5pt">Why choose Spec CPU 2006 instead of Spec CPU 2017? Do you have results on
<span style="color:black">Spec CPU 2017?</span></span></p>
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<span style="font-size:10.5pt"><span style="">2.<span style="font:7.0pt "Times New Roman"">
</span></span></span><span class="x_pocket-ignore"><span style="font-size:10.5pt"></span></span><span style="font-size:10.5pt">Please point out if there
<span class="x_grammar-check-ignore">is</span> any <span class="x_grammar-check-ignore">
error</span> with my usage of <span style="color:black">CSSPGO, the steps are as follows:</span></span></p>
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<span style="font-size:10.5pt">Suppose that my program is test.cpp.</span></p>
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<span style="font-size:10.5pt">Step 1: <span style="color:black; background:white">
clang -O3 -g3 -fno-omit-frame-pointer -fdebug-info-for-profiling -fpseudo-probe-for-profiling test.cpp -o test</span></span></p>
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<span style="font-size:10.5pt; color:black; background:white">Step 2: </span><span style="font-size:10.5pt; font-family:SourceCodeProMac; color:black; background:white">perf record -g --call-graph fp -e br_inst_retired.near_taken:uppp -c 16009 -b -o
test.perf.data ./test</span><span style="font-size:10.5pt"></span></p>
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<span style="font-size:10.5pt; font-family:SourceCodeProMac; color:black; background:white">Step 3: perf script -F ip,brstack -i test.perf.data --show-mmap-event &> test.perf.script</span><span style="font-size:10.5pt"></span></p>
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<span style="font-size:10.5pt; font-family:SourceCodeProMac; color:black; background:white">Step 4: llvm_install/bin/llvm-profgen --perfscript=test.perf.script --binary=./test --output=test.spgo.profraw --format=text</span><span style="font-size:10.5pt"></span></p>
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<span style="font-size:10.5pt; font-family:SourceCodeProMac; color:black; background:white">Step 5: llvm_install/bin/llvm-profdata merge --text --sample -output=test.spgo.prof test.profraw ...</span><span style="font-size:10.5pt"></span></p>
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<span style="font-size:10.5pt; font-family:SourceCodeProMac; color:black; background:white">Step 6: clang -O3 -g3 -fpseudo-probe-for-profiling --fprofile-sample-use=test.spgo.prof test.cpp -o cs_test</span><span style="font-size:10.5pt"></span></p>
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<span style="font-size:10.5pt; font-family:SourceCodeProMac; color:black; background:white">Step 7: ./cs_test</span><span style="font-size:10.5pt"></span></p>
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<span style="font-size:10.5pt"> </span></p>
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<span style="font-size:10.5pt; font-family:SourceCodeProMac; color:black; background:white">Thanks,</span><span style="font-size:10.5pt"></span></p>
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<span style="font-size:10.5pt; font-family:SourceCodeProMac; color:black; background:white">Qingqing Xu</span><span style="font-size:10.5pt"></span></p>
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<span class="x_outer-u-container"><span style="font-size:10.5pt"><a href="mailto:*llvm-dev@lists.llvm.org" rel="nofollow noopener noreferrer"><span style="color:#3370ff; text-decoration:none"><span></span></span></a><a href="mailto:llvm-dev@lists.llvm.org" rel="nofollow noopener noreferrer">llvm-dev@lists.llvm.org</a></span></span><span style="font-size:10.5pt"></span></p>
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