quote:

In the one set of FIO tests, 64 KB block sizes were used, with one core is pegged with two NVM-Express flash drives, and the idea was to just hammer that core as much as possible. Thanks to the Skylake architecture change, there was no performance impact. On the Broadwell machines, there was a 30 percent hit and on Haswell there was a 27 percent hit. Shifting to a smaller 4 KB block size with the same two NVM-Express drives hitting a single core, the Skylake machine Took a 32 percent performance hit running the FIO test, and the Broadwell machine saw its performance drop by 59 percent and the Haswell by 60 percent. All that boundary crossing really hurts performance.

Now, because the FIO hit was so bad, another set of FIO benchmark test code was used, but this time with the Retpoline changes in its code as Google has suggested, for both scenarios – 64 KB and 4 KB block sizes. With the 64 KB block size scenario, there was no change in the Skylake machine because it wasn’t impacted at all by the microcode and operating system patches. But on the Broadwell system tested the 64 KB block size, after Retpoline techniques were applied, the hit was only 2 percent and on the Haswell system tested it was only 1 percent. No big deal, as Google said in its original post. Now, with 4 KB block sizes, it is still a big deal, but the performance impact was a lot lower once the Retpoline approaches were used. The Skylake machine only lost 18 percent of its performance after applying the Spectre and Meltdown patches, the Broadwell machine only lost 22 percent, and the Haswell machine only lost 20 percent. While this is not great, it is better than it could be.

quote:

Orijinalden alıntı: Mete Can Karahasan

Sen aynı tas, aynı hamam devam et. Eski yamayla %32, yenisiyle ise %18.

quote: In the one set of FIO tests, 64 KB block sizes were used, with one core is pegged with two NVM-Express flash drives, and the idea was to just hammer that core as much as possible. Thanks to the Skylake architecture change, there was no performance impact. On the Broadwell machines, there was a 30 percent hit and on Haswell there was a 27 percent hit. Shifting to a smaller 4 KB block size with the same two NVM-Express drives hitting a single core, the Skylake machine Took a 32 percent performance hit running the FIO test, and the Broadwell machine saw its performance drop by 59 percent and the Haswell by 60 percent. All that boundary crossing really hurts performance. Now, because the FIO hit was so bad, another set of FIO benchmark test code was used, but this time with the Retpoline changes in its code as Google has suggested, for both scenarios – 64 KB and 4 KB block sizes. With the 64 KB block size scenario, there was no change in the Skylake machine because it wasn’t impacted at all by the microcode and operating system patches. But on the Broadwell system tested the 64 KB block size, after Retpoline techniques were applied, the hit was only 2 percent and on the Haswell system tested it was only 1 percent. No big deal, as Google said in its original post. Now, with 4 KB block sizes, it is still a big deal, but the performance impact was a lot lower once the Retpoline approaches were used. The Skylake machine only lost 18 percent of its performance after applying the Spectre and Meltdown patches, the Broadwell machine only lost 22 percent, and the Haswell machine only lost 20 percent. While this is not great, it is better than it could be.

[Kaynak]

quote:

Biraz araya mesafe koymam gerek.